diff --git a/app/routes/teams.py b/app/routes/teams.py
index b876d89..1dabb16 100644
--- a/app/routes/teams.py
+++ b/app/routes/teams.py
@@ -29,7 +29,7 @@ from app.models import (
     User,
 )
 from app.permissions import visible_org_teams
-from app.validators import OrgTeamSchema
+from app.validators import OrgTeamSchema, TeamPlayerSchema, TeamStaffSchema
 
 teams_bp = Blueprint('teams', __name__, url_prefix='/teams')
 
@@ -55,7 +55,12 @@ def list_teams():
     managers = (
         User.query.filter_by(role='manager', is_active_account=True).order_by(User.username).all()
     )
-    all_players = User.query.filter_by(role='player').order_by(User.username).all()
+    # is_active_account, like the two queries above it. Without it the "add
+    # player" select offered accounts that had been deactivated, and
+    # add_player accepted them.
+    all_players = (
+        User.query.filter_by(role='player', is_active_account=True).order_by(User.username).all()
+    )
     return render_template(
         'pages/teams.html',
         teams=teams,
@@ -119,27 +124,58 @@ def my_teams():
     return render_template('pages/my_teams.html', team_data=team_data, now=now)
 
 
-def _staff_member(user_id, expected_class):
-    """The user behind an id, only if they hold the role being assigned.
+def _posted(schema):
+    """Load a form through `schema`, or None when it will not load.
 
-    Returns None for a missing id, an unknown id, or an account of the wrong
-    role. That last case is the point (SEC-16): the id comes from a `<select>`
-    the browser rendered, so it is a value the client chooses, and nothing
-    checked it in two of the three places that used it. A forged submission
-    could therefore list a player among a team's coaches — the same defect
-    wave G fixed in `tryouts.py`, left standing here.
+    The five assignment routes below each answer a bad field with their own
+    flash and a redirect to the same page, so a shared "it did not validate"
+    return is enough; the field-level message is flashed on the way out.
+    """
+    try:
+        return schema.load(form_payload())
+    except ValidationError as err:
+        flash_validation_errors(err)
+        return None
+
+
+def _assignable(user, expected_class):
+    """Whether this account may be given a role on a team.
+
+    Deactivated accounts were offered by the selects and accepted by the
+    routes. `is_active_account` is what stops someone logging in — a person
+    who has left the club — so putting them on a roster contradicts the one
+    control that says they are gone. The listings filtered it for coaches and
+    managers and not for players, two lines apart, which is how it went
+    unnoticed.
+    """
+    return isinstance(user, expected_class) and bool(user.is_active_account)
+
+
+def _staff_member(user_id, expected_class):
+    """The user behind an id, only if they may hold the role being assigned.
+
+    Returns None for a missing id, an unknown id, an account of the wrong
+    role, or a deactivated one. The role check is the point (SEC-16): the id
+    comes from a `<select>` the browser rendered, so it is a value the client
+    chooses, and nothing checked it in two of the three places that used it.
+    A forged submission could therefore list a player among a team's coaches
+    — the same defect wave G fixed in `tryouts.py`, left standing here.
+
+    Defers to `_assignable` rather than repeating `isinstance`: two functions
+    in one file answering "may this account take this role" differently is
+    the shape of every defect this module has had.
 
     Args:
-        user_id: Already an int or None, thanks to OrgTeamSchema.
+        user_id: Already an int or None, thanks to the schema.
         expected_class: Coach or Manager.
 
     Returns:
-        User | None: The account, when it is of the expected role.
+        User | None: The account, when it may take the role.
     """
     if not user_id:
         return None
     user = db.session.get(User, user_id)
-    return user if isinstance(user, expected_class) else None
+    return user if user and _assignable(user, expected_class) else None
 
 
 @teams_bp.route('/create', methods=['POST'])
@@ -305,13 +341,15 @@ def add_coach(team_id):
         flash(_('Permission denied.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
-    coach_id = request.form.get('coach_id')
-    if not coach_id:
+    data = _posted(TeamStaffSchema())
+    if data is None:
+        return redirect(url_for('teams.list_teams'))
+    if not data['coach_id']:
         flash(_('Please select a coach.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
-    coach = User.query.get_or_404(int(coach_id))
-    if not isinstance(coach, Coach):
+    coach = db.session.get(User, data['coach_id'])
+    if not coach or not _assignable(coach, Coach):
         flash(_('Only coaches can be assigned as coach.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
@@ -346,13 +384,15 @@ def add_manager(team_id):
         flash(_('Permission denied.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
-    manager_id = request.form.get('manager_id')
-    if not manager_id:
+    data = _posted(TeamStaffSchema())
+    if data is None:
+        return redirect(url_for('teams.list_teams'))
+    if not data['manager_id']:
         flash(_('Please select a manager.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
-    manager = User.query.get_or_404(int(manager_id))
-    if not isinstance(manager, Manager):
+    manager = db.session.get(User, data['manager_id'])
+    if not manager or not _assignable(manager, Manager):
         flash(_('Only managers can be assigned as manager.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
@@ -387,9 +427,12 @@ def remove_coach(team_id):
         flash(_('Permission denied.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
-    coach_id = request.form.get('coach_id')
-    if coach_id:
-        coach = User.query.get(int(coach_id))
+    data = _posted(TeamStaffSchema())
+    if data is None:
+        return redirect(url_for('teams.list_teams'))
+
+    if data['coach_id']:
+        coach = db.session.get(User, data['coach_id'])
         if coach and team.coaches.filter_by(id=coach.id).first():
             team.coaches.remove(coach)
             if team.coach_id == coach.id:
@@ -412,9 +455,12 @@ def remove_manager(team_id):
         flash(_('Permission denied.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
-    manager_id = request.form.get('manager_id')
-    if manager_id:
-        manager = User.query.get(int(manager_id))
+    data = _posted(TeamStaffSchema())
+    if data is None:
+        return redirect(url_for('teams.list_teams'))
+
+    if data['manager_id']:
+        manager = db.session.get(User, data['manager_id'])
         if manager and team.managers.filter_by(id=manager.id).first():
             team.managers.remove(manager)
             if team.manager_id == manager.id:
@@ -437,14 +483,16 @@ def add_player(team_id):
         flash(_('Permission denied.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
-    player_id = request.form.get('player_id')
-    status = request.form.get('status', 'starter')
-    if not player_id:
+    data = _posted(TeamPlayerSchema())
+    if data is None:
+        return redirect(url_for('teams.list_teams'))
+    if not data['player_id']:
         flash(_('Please select a player.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
-    player = User.query.get_or_404(int(player_id))
-    if not isinstance(player, Player):
+    status = data['status']
+    player = db.session.get(User, data['player_id'])
+    if not player or not _assignable(player, Player):
         flash(_('Can only assign players to teams.'), 'danger')
         return redirect(url_for('teams.list_teams'))
 
diff --git a/app/routes/tryouts.py b/app/routes/tryouts.py
index df213be..4d375e9 100644
--- a/app/routes/tryouts.py
+++ b/app/routes/tryouts.py
@@ -303,7 +303,14 @@ def view_tryout(tryout_id):
 
     all_players = None
     if can_edit:
-        all_players = User.query.filter_by(role='player').order_by(User.username).all()
+        # is_active_account, like the manager and coach queries in this same
+        # module. Offering a deactivated account in a roster select
+        # contradicts the one control that says the person has left.
+        all_players = (
+            User.query.filter_by(role='player', is_active_account=True)
+            .order_by(User.username)
+            .all()
+        )
 
     matches = (
         Match.query.filter_by(tryout_id=tryout_id).order_by(Match.date, Match.start_time).all()
diff --git a/app/translations/en/LC_MESSAGES/messages.mo b/app/translations/en/LC_MESSAGES/messages.mo
index 4ecf618..23c3123 100644
Binary files a/app/translations/en/LC_MESSAGES/messages.mo and b/app/translations/en/LC_MESSAGES/messages.mo differ
diff --git a/app/translations/en/LC_MESSAGES/messages.po b/app/translations/en/LC_MESSAGES/messages.po
index 987f8c3..e4301be 100644
--- a/app/translations/en/LC_MESSAGES/messages.po
+++ b/app/translations/en/LC_MESSAGES/messages.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: team-tryouts VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2026-08-11 20:15-0400\n"
+"POT-Creation-Date: 2026-08-11 20:39-0400\n"
 "PO-Revision-Date: 2026-08-07 20:22-0400\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language: en\n"
@@ -90,127 +90,135 @@ msgstr "Player must be selected."
 msgid "Notes must be 2000 characters or less."
 msgstr "Notes must be 2000 characters or less."
 
-#: app/validators.py:482
-msgid "Date must be in YYYY-MM-DD format."
-msgstr "Date must be in YYYY-MM-DD format."
-
-#: app/validators.py:483
-msgid "A date is required."
-msgstr "A date is required."
-
-#: app/validators.py:489 app/validators.py:554
-msgid "Start time must be in HH:MM format."
-msgstr "Start time must be in HH:MM format."
-
-#: app/validators.py:490 app/validators.py:555
-msgid "A start time is required."
-msgstr "A start time is required."
-
-#: app/validators.py:496
-msgid "End time must be in HH:MM format."
-msgstr "End time must be in HH:MM format."
-
-#: app/validators.py:497
-msgid "An end time is required."
-msgstr "An end time is required."
-
-#: app/validators.py:501
-msgid "Points must be 2000 characters or less."
-msgstr "Points must be 2000 characters or less."
-
-#: app/validators.py:516
-msgid "End time must be after start time."
-msgstr "End time must be after start time."
-
-#: app/validators.py:545 app/validators.py:547
-msgid "Day must be 0 (Monday) to 6 (Sunday)."
-msgstr "Day must be 0 (Monday) to 6 (Sunday)."
-
-#: app/validators.py:548
-msgid "A day is required."
-msgstr "A day is required."
-
-#: app/validators.py:583
-msgid "Player selection is malformed."
-msgstr "Player selection is malformed."
-
-#: app/validators.py:609 app/validators.py:719
-msgid "A title is required."
-msgstr "A title is required."
-
-#: app/validators.py:618
-msgid "Invalid date format."
-msgstr "Invalid date format."
-
-#: app/validators.py:623 app/validators.py:630
-msgid "Invalid time format."
-msgstr "Invalid time format."
-
-#: app/validators.py:624
-msgid "Start time is required. Please select a time slot."
-msgstr "Start time is required. Please select a time slot."
-
-#: app/validators.py:638
-msgid "Unknown match status."
-msgstr "Unknown match status."
-
-#: app/validators.py:654
-msgid "The end time must come after the start time."
-msgstr "The end time must come after the start time."
-
-#: app/validators.py:668
-msgid "Unknown match type."
-msgstr "Unknown match type."
-
-#: app/validators.py:680
-msgid "A team cannot play against itself."
-msgstr "A team cannot play against itself."
-
-#: app/validators.py:728
-msgid "Unknown game."
-msgstr "Unknown game."
-
-#: app/validators.py:733
-msgid "Invalid start date format."
-msgstr "Invalid start date format."
-
-#: app/validators.py:734
-msgid "A start date is required."
-msgstr "A start date is required."
-
-#: app/validators.py:740
-msgid "Invalid end date format."
-msgstr "Invalid end date format."
-
-#: app/validators.py:748
-msgid "A tryout must allow at least one player."
-msgstr "A tryout must allow at least one player."
-
-#: app/validators.py:751
-msgid "The player limit must be a whole number."
-msgstr "The player limit must be a whole number."
-
-#: app/validators.py:763
-msgid "End date cannot be before start date."
-msgstr "End date cannot be before start date."
-
-#: app/validators.py:790 app/validators.py:791
-msgid "Team name is required."
-msgstr "Team name is required."
-
-#: app/validators.py:797
+#: app/validators.py:494 app/validators.py:853
 msgid "Invalid coach selection."
 msgstr "Invalid coach selection."
 
-#: app/validators.py:803
+#: app/validators.py:500 app/validators.py:859
 msgid "Invalid manager selection."
 msgstr "Invalid manager selection."
 
-#: app/validators.py:815
+#: app/validators.py:511
+msgid "Invalid player selection."
+msgstr "Invalid player selection."
+
+#: app/validators.py:515
+msgid "Unknown roster status."
+msgstr "Unknown roster status."
+
+#: app/validators.py:538
+msgid "Date must be in YYYY-MM-DD format."
+msgstr "Date must be in YYYY-MM-DD format."
+
+#: app/validators.py:539
+msgid "A date is required."
+msgstr "A date is required."
+
+#: app/validators.py:545 app/validators.py:610
+msgid "Start time must be in HH:MM format."
+msgstr "Start time must be in HH:MM format."
+
+#: app/validators.py:546 app/validators.py:611
+msgid "A start time is required."
+msgstr "A start time is required."
+
+#: app/validators.py:552
+msgid "End time must be in HH:MM format."
+msgstr "End time must be in HH:MM format."
+
+#: app/validators.py:553
+msgid "An end time is required."
+msgstr "An end time is required."
+
+#: app/validators.py:557
+msgid "Points must be 2000 characters or less."
+msgstr "Points must be 2000 characters or less."
+
+#: app/validators.py:572
+msgid "End time must be after start time."
+msgstr "End time must be after start time."
+
+#: app/validators.py:601 app/validators.py:603
+msgid "Day must be 0 (Monday) to 6 (Sunday)."
+msgstr "Day must be 0 (Monday) to 6 (Sunday)."
+
+#: app/validators.py:604
+msgid "A day is required."
+msgstr "A day is required."
+
+#: app/validators.py:639
+msgid "Player selection is malformed."
+msgstr "Player selection is malformed."
+
+#: app/validators.py:665 app/validators.py:775
+msgid "A title is required."
+msgstr "A title is required."
+
+#: app/validators.py:674
+msgid "Invalid date format."
+msgstr "Invalid date format."
+
+#: app/validators.py:679 app/validators.py:686
+msgid "Invalid time format."
+msgstr "Invalid time format."
+
+#: app/validators.py:680
+msgid "Start time is required. Please select a time slot."
+msgstr "Start time is required. Please select a time slot."
+
+#: app/validators.py:694
+msgid "Unknown match status."
+msgstr "Unknown match status."
+
+#: app/validators.py:710
+msgid "The end time must come after the start time."
+msgstr "The end time must come after the start time."
+
+#: app/validators.py:724
+msgid "Unknown match type."
+msgstr "Unknown match type."
+
+#: app/validators.py:736
+msgid "A team cannot play against itself."
+msgstr "A team cannot play against itself."
+
+#: app/validators.py:784
+msgid "Unknown game."
+msgstr "Unknown game."
+
+#: app/validators.py:789
+msgid "Invalid start date format."
+msgstr "Invalid start date format."
+
+#: app/validators.py:790
+msgid "A start date is required."
+msgstr "A start date is required."
+
+#: app/validators.py:796
+msgid "Invalid end date format."
+msgstr "Invalid end date format."
+
+#: app/validators.py:804
+msgid "A tryout must allow at least one player."
+msgstr "A tryout must allow at least one player."
+
+#: app/validators.py:807
+msgid "The player limit must be a whole number."
+msgstr "The player limit must be a whole number."
+
+#: app/validators.py:819
+msgid "End date cannot be before start date."
+msgstr "End date cannot be before start date."
+
+#: app/validators.py:846 app/validators.py:847
+msgid "Team name is required."
+msgstr "Team name is required."
+
+#: app/validators.py:871
 msgid "Scores run from 1 to 10."
 msgstr "Scores run from 1 to 10."
 
-#: app/validators.py:816
+#: app/validators.py:872
 msgid "A score must be a whole number from 1 to 10."
 msgstr "A score must be a whole number from 1 to 10."
 
@@ -311,12 +319,12 @@ msgstr "Evaluation submitted successfully!"
 msgid "Evaluation updated!"
 msgstr "Evaluation updated!"
 
-#: app/routes/evaluations.py:210 app/routes/teams.py:305
-#: app/routes/teams.py:346 app/routes/teams.py:387 app/routes/teams.py:412
-#: app/routes/teams.py:437 app/routes/teams.py:472 app/routes/tryouts.py:437
-#: app/routes/tryouts.py:453 app/routes/tryouts.py:473
-#: app/routes/tryouts.py:512 app/routes/tryouts.py:548
-#: app/routes/tryouts.py:567
+#: app/routes/evaluations.py:210 app/routes/teams.py:341
+#: app/routes/teams.py:384 app/routes/teams.py:427 app/routes/teams.py:455
+#: app/routes/teams.py:483 app/routes/teams.py:520 app/routes/tryouts.py:444
+#: app/routes/tryouts.py:460 app/routes/tryouts.py:480
+#: app/routes/tryouts.py:519 app/routes/tryouts.py:555
+#: app/routes/tryouts.py:574
 msgid "Permission denied."
 msgstr "Permission denied."
 
@@ -373,130 +381,130 @@ msgstr "Use My Team(s) to view your teams."
 msgid "You do not have permission to view teams."
 msgstr "You do not have permission to view teams."
 
-#: app/routes/teams.py:74
+#: app/routes/teams.py:79
 msgid "This page is for players."
 msgstr "This page is for players."
 
-#: app/routes/teams.py:150
+#: app/routes/teams.py:186
 msgid "You do not have permission to create teams."
 msgstr "You do not have permission to create teams."
 
-#: app/routes/teams.py:161 app/routes/teams.py:203
+#: app/routes/teams.py:197 app/routes/teams.py:239
 #, python-format
 msgid "Team \"%(name)s\" already exists."
 msgstr "Team \"%(name)s\" already exists."
 
-#: app/routes/teams.py:182
+#: app/routes/teams.py:218
 #, python-format
 msgid "Team \"%(name)s\" created successfully!"
 msgstr "Team \"%(name)s\" created successfully!"
 
-#: app/routes/teams.py:192
+#: app/routes/teams.py:228
 msgid "You do not have permission to edit this team."
 msgstr "You do not have permission to edit this team."
 
-#: app/routes/teams.py:236
+#: app/routes/teams.py:272
 #, python-format
 msgid "Team \"%(name)s\" updated successfully!"
 msgstr "Team \"%(name)s\" updated successfully!"
 
-#: app/routes/teams.py:264
+#: app/routes/teams.py:300
 msgid "You do not have permission to delete teams."
 msgstr "You do not have permission to delete teams."
 
-#: app/routes/teams.py:295
+#: app/routes/teams.py:331
 #, python-format
 msgid "Team \"%(name)s\" deleted successfully."
 msgstr "Team \"%(name)s\" deleted successfully."
 
-#: app/routes/teams.py:310
+#: app/routes/teams.py:348
 msgid "Please select a coach."
 msgstr "Please select a coach."
 
-#: app/routes/teams.py:315
+#: app/routes/teams.py:353
 msgid "Only coaches can be assigned as coach."
 msgstr "Only coaches can be assigned as coach."
 
-#: app/routes/teams.py:321
+#: app/routes/teams.py:359
 #, python-format
 msgid "%(username)s is already a coach of %(name)s."
 msgstr "%(username)s is already a coach of %(name)s."
 
-#: app/routes/teams.py:334
+#: app/routes/teams.py:372
 #, python-format
 msgid "%(username)s added as coach of %(name)s."
 msgstr "%(username)s added as coach of %(name)s."
 
-#: app/routes/teams.py:351
+#: app/routes/teams.py:391
 msgid "Please select a manager."
 msgstr "Please select a manager."
 
-#: app/routes/teams.py:356
+#: app/routes/teams.py:396
 msgid "Only managers can be assigned as manager."
 msgstr "Only managers can be assigned as manager."
 
-#: app/routes/teams.py:362
+#: app/routes/teams.py:402
 #, python-format
 msgid "%(username)s is already a manager of %(name)s."
 msgstr "%(username)s is already a manager of %(name)s."
 
-#: app/routes/teams.py:375
+#: app/routes/teams.py:415
 #, python-format
 msgid "%(username)s added as manager of %(name)s."
 msgstr "%(username)s added as manager of %(name)s."
 
-#: app/routes/teams.py:402
+#: app/routes/teams.py:445
 #, python-format
 msgid "Coach removed from %(name)s."
 msgstr "Coach removed from %(name)s."
 
-#: app/routes/teams.py:427
+#: app/routes/teams.py:473
 #, python-format
 msgid "Manager removed from %(name)s."
 msgstr "Manager removed from %(name)s."
 
-#: app/routes/teams.py:443 app/routes/tryouts.py:477 app/routes/tryouts.py:578
+#: app/routes/teams.py:490 app/routes/tryouts.py:484 app/routes/tryouts.py:585
 msgid "Please select a player."
 msgstr "Please select a player."
 
-#: app/routes/teams.py:448
+#: app/routes/teams.py:496
 msgid "Can only assign players to teams."
 msgstr "Can only assign players to teams."
 
-#: app/routes/teams.py:454
+#: app/routes/teams.py:502
 #, python-format
 msgid "%(username)s is already on %(name)s."
 msgstr "%(username)s is already on %(name)s."
 
-#: app/routes/teams.py:462
+#: app/routes/teams.py:510
 #, python-format
 msgid "%(username)s added to %(name)s!"
 msgstr "%(username)s added to %(name)s!"
 
-#: app/routes/teams.py:479 app/routes/teams.py:553
+#: app/routes/teams.py:527 app/routes/teams.py:601
 #, python-format
 msgid "%(username)s is not on %(name)s."
 msgstr "%(username)s is not on %(name)s."
 
-#: app/routes/teams.py:487
+#: app/routes/teams.py:535
 #, python-format
 msgid "%(username)s removed from %(name)s."
 msgstr "%(username)s removed from %(name)s."
 
-#: app/routes/teams.py:524 app/routes/teams.py:542
+#: app/routes/teams.py:572 app/routes/teams.py:590
 msgid "You do not have permission to add notes to this team."
 msgstr "You do not have permission to add notes to this team."
 
-#: app/routes/teams.py:532
+#: app/routes/teams.py:580
 msgid "Team notes added successfully!"
 msgstr "Team notes added successfully!"
 
-#: app/routes/teams.py:547 app/routes/users/notes.py:207
+#: app/routes/teams.py:595 app/routes/users/notes.py:207
 #: app/routes/users/notes.py:250
 msgid "Can only add notes for players."
 msgstr "Can only add notes for players."
 
-#: app/routes/teams.py:563
+#: app/routes/teams.py:611
 #, python-format
 msgid "Note added for %(username)s!"
 msgstr "Note added for %(username)s!"
@@ -525,76 +533,76 @@ msgstr "Tryout updated successfully!"
 msgid "You do not have permission to view this tryout."
 msgstr "You do not have permission to view this tryout."
 
-#: app/routes/tryouts.py:404
+#: app/routes/tryouts.py:411
 msgid "Only players can register for tryouts."
 msgstr "Only players can register for tryouts."
 
-#: app/routes/tryouts.py:408
+#: app/routes/tryouts.py:415
 msgid "This tryout is not accepting registrations."
 msgstr "This tryout is not accepting registrations."
 
-#: app/routes/tryouts.py:415
+#: app/routes/tryouts.py:422
 msgid "You are already registered for this tryout."
 msgstr "You are already registered for this tryout."
 
-#: app/routes/tryouts.py:421 app/routes/tryouts.py:496
+#: app/routes/tryouts.py:428 app/routes/tryouts.py:503
 msgid "This tryout is full."
 msgstr "This tryout is full."
 
-#: app/routes/tryouts.py:427
+#: app/routes/tryouts.py:434
 msgid "Successfully registered for tryout!"
 msgstr "Successfully registered for tryout!"
 
-#: app/routes/tryouts.py:443
+#: app/routes/tryouts.py:450
 #, python-format
 msgid "Tryout status updated to %(new_status)s."
 msgstr "Tryout status updated to %(new_status)s."
 
-#: app/routes/tryouts.py:463
+#: app/routes/tryouts.py:470
 msgid "Registration status updated."
 msgstr "Registration status updated."
 
-#: app/routes/tryouts.py:482
+#: app/routes/tryouts.py:489
 msgid "Can only register players."
 msgstr "Can only register players."
 
-#: app/routes/tryouts.py:488
+#: app/routes/tryouts.py:495
 #, python-format
 msgid "%(username)s is already registered for this tryout."
 msgstr "%(username)s is already registered for this tryout."
 
-#: app/routes/tryouts.py:502
+#: app/routes/tryouts.py:509
 #, python-format
 msgid "%(username)s registered for tryout!"
 msgstr "%(username)s registered for tryout!"
 
-#: app/routes/tryouts.py:538
+#: app/routes/tryouts.py:545
 #, python-format
 msgid "%(username)s removed from tryout."
 msgstr "%(username)s removed from tryout."
 
-#: app/routes/tryouts.py:556
+#: app/routes/tryouts.py:563
 #, python-format
 msgid "Team \"%(team_name)s\" created!"
 msgstr "Team \"%(team_name)s\" created!"
 
-#: app/routes/tryouts.py:587
+#: app/routes/tryouts.py:594
 msgid "That player is not registered for this tryout."
 msgstr "That player is not registered for this tryout."
 
-#: app/routes/tryouts.py:593
+#: app/routes/tryouts.py:600
 msgid "Player is already on this team."
 msgstr "Player is already on this team."
 
-#: app/routes/tryouts.py:598
+#: app/routes/tryouts.py:605
 msgid "Player added to team!"
 msgstr "Player added to team!"
 
-#: app/routes/tryouts.py:608
+#: app/routes/tryouts.py:615
 msgid "You do not have permission to delete this tryout."
 msgstr "You do not have permission to delete this tryout."
 
-#: app/routes/tryouts.py:644
+#: app/routes/tryouts.py:651
 msgid "Tryout deleted successfully."
 msgstr "Tryout deleted successfully."
 
diff --git a/app/translations/fr/LC_MESSAGES/messages.mo b/app/translations/fr/LC_MESSAGES/messages.mo
index 0d14709..b9f3180 100644
Binary files a/app/translations/fr/LC_MESSAGES/messages.mo and b/app/translations/fr/LC_MESSAGES/messages.mo differ
diff --git a/app/translations/fr/LC_MESSAGES/messages.po b/app/translations/fr/LC_MESSAGES/messages.po
index 4a33801..690e0cc 100644
--- a/app/translations/fr/LC_MESSAGES/messages.po
+++ b/app/translations/fr/LC_MESSAGES/messages.po
@@ -8,7 +8,7 @@ msgid ""
 msgstr ""
 "Project-Id-Version: team-tryouts VERSION\n"
 "Report-Msgid-Bugs-To: EMAIL@ADDRESS\n"
-"POT-Creation-Date: 2026-08-11 20:15-0400\n"
+"POT-Creation-Date: 2026-08-11 20:39-0400\n"
 "PO-Revision-Date: 2026-08-07 20:22-0400\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language: fr\n"
@@ -92,127 +92,135 @@ msgstr "Vous devez choisir un joueur."
 msgid "Notes must be 2000 characters or less."
 msgstr "Les notes ne doivent pas dépasser 2000 caractères."
 
-#: app/validators.py:482
-msgid "Date must be in YYYY-MM-DD format."
-msgstr "La date doit être au format AAAA-MM-JJ."
-
-#: app/validators.py:483
-msgid "A date is required."
-msgstr "Une date est requise."
-
-#: app/validators.py:489 app/validators.py:554
-msgid "Start time must be in HH:MM format."
-msgstr "L’heure de début doit être au format HH:MM."
-
-#: app/validators.py:490 app/validators.py:555
-msgid "A start time is required."
-msgstr "Une heure de début est requise."
-
-#: app/validators.py:496
-msgid "End time must be in HH:MM format."
-msgstr "L’heure de fin doit être au format HH:MM."
-
-#: app/validators.py:497
-msgid "An end time is required."
-msgstr "Une heure de fin est requise."
-
-#: app/validators.py:501
-msgid "Points must be 2000 characters or less."
-msgstr "Les points ne doivent pas dépasser 2000 caractères."
-
-#: app/validators.py:516
-msgid "End time must be after start time."
-msgstr "L'heure de fin doit être postérieure à l'heure de début."
-
-#: app/validators.py:545 app/validators.py:547
-msgid "Day must be 0 (Monday) to 6 (Sunday)."
-msgstr "Le jour doit aller de 0 (lundi) à 6 (dimanche)."
-
-#: app/validators.py:548
-msgid "A day is required."
-msgstr "Un jour est requis."
-
-#: app/validators.py:583
-msgid "Player selection is malformed."
-msgstr "La sélection de joueurs est mal formée."
-
-#: app/validators.py:609 app/validators.py:719
-msgid "A title is required."
-msgstr "Un titre est requis."
-
-#: app/validators.py:618
-msgid "Invalid date format."
-msgstr "Format de date invalide."
-
-#: app/validators.py:623 app/validators.py:630
-msgid "Invalid time format."
-msgstr "Format d’heure invalide."
-
-#: app/validators.py:624
-msgid "Start time is required. Please select a time slot."
-msgstr "L’heure de début est obligatoire. Choisissez une plage horaire."
-
-#: app/validators.py:638
-msgid "Unknown match status."
-msgstr "Statut de match inconnu."
-
-#: app/validators.py:654
-msgid "The end time must come after the start time."
-msgstr "L'heure de fin doit être postérieure à l'heure de début."
-
-#: app/validators.py:668
-msgid "Unknown match type."
-msgstr "Type de match inconnu."
-
-#: app/validators.py:680
-msgid "A team cannot play against itself."
-msgstr "Une équipe ne peut pas jouer contre elle-même."
-
-#: app/validators.py:728
-msgid "Unknown game."
-msgstr "Jeu inconnu."
-
-#: app/validators.py:733
-msgid "Invalid start date format."
-msgstr "Format de date de début invalide."
-
-#: app/validators.py:734
-msgid "A start date is required."
-msgstr "Une date de début est requise."
-
-#: app/validators.py:740
-msgid "Invalid end date format."
-msgstr "Format de date de fin invalide."
-
-#: app/validators.py:748
-msgid "A tryout must allow at least one player."
-msgstr "Une sélection doit accepter au moins un joueur."
-
-#: app/validators.py:751
-msgid "The player limit must be a whole number."
-msgstr "La limite de joueurs doit être un nombre entier."
-
-#: app/validators.py:763
-msgid "End date cannot be before start date."
-msgstr "La date de fin ne peut pas précéder la date de début."
-
-#: app/validators.py:790 app/validators.py:791
-msgid "Team name is required."
-msgstr "Le nom de l’équipe est obligatoire."
-
-#: app/validators.py:797
+#: app/validators.py:494 app/validators.py:853
 msgid "Invalid coach selection."
 msgstr "Sélection de coach invalide."
 
-#: app/validators.py:803
+#: app/validators.py:500 app/validators.py:859
 msgid "Invalid manager selection."
 msgstr "Sélection de gérant invalide."
 
-#: app/validators.py:815
+#: app/validators.py:511
+msgid "Invalid player selection."
+msgstr "Sélection de joueur invalide."
+
+#: app/validators.py:515
+msgid "Unknown roster status."
+msgstr "Statut d'effectif inconnu."
+
+#: app/validators.py:538
+msgid "Date must be in YYYY-MM-DD format."
+msgstr "La date doit être au format AAAA-MM-JJ."
+
+#: app/validators.py:539
+msgid "A date is required."
+msgstr "Une date est requise."
+
+#: app/validators.py:545 app/validators.py:610
+msgid "Start time must be in HH:MM format."
+msgstr "L’heure de début doit être au format HH:MM."
+
+#: app/validators.py:546 app/validators.py:611
+msgid "A start time is required."
+msgstr "Une heure de début est requise."
+
+#: app/validators.py:552
+msgid "End time must be in HH:MM format."
+msgstr "L’heure de fin doit être au format HH:MM."
+
+#: app/validators.py:553
+msgid "An end time is required."
+msgstr "Une heure de fin est requise."
+
+#: app/validators.py:557
+msgid "Points must be 2000 characters or less."
+msgstr "Les points ne doivent pas dépasser 2000 caractères."
+
+#: app/validators.py:572
+msgid "End time must be after start time."
+msgstr "L'heure de fin doit être postérieure à l'heure de début."
+
+#: app/validators.py:601 app/validators.py:603
+msgid "Day must be 0 (Monday) to 6 (Sunday)."
+msgstr "Le jour doit aller de 0 (lundi) à 6 (dimanche)."
+
+#: app/validators.py:604
+msgid "A day is required."
+msgstr "Un jour est requis."
+
+#: app/validators.py:639
+msgid "Player selection is malformed."
+msgstr "La sélection de joueurs est mal formée."
+
+#: app/validators.py:665 app/validators.py:775
+msgid "A title is required."
+msgstr "Un titre est requis."
+
+#: app/validators.py:674
+msgid "Invalid date format."
+msgstr "Format de date invalide."
+
+#: app/validators.py:679 app/validators.py:686
+msgid "Invalid time format."
+msgstr "Format d’heure invalide."
+
+#: app/validators.py:680
+msgid "Start time is required. Please select a time slot."
+msgstr "L’heure de début est obligatoire. Choisissez une plage horaire."
+
+#: app/validators.py:694
+msgid "Unknown match status."
+msgstr "Statut de match inconnu."
+
+#: app/validators.py:710
+msgid "The end time must come after the start time."
+msgstr "L'heure de fin doit être postérieure à l'heure de début."
+
+#: app/validators.py:724
+msgid "Unknown match type."
+msgstr "Type de match inconnu."
+
+#: app/validators.py:736
+msgid "A team cannot play against itself."
+msgstr "Une équipe ne peut pas jouer contre elle-même."
+
+#: app/validators.py:784
+msgid "Unknown game."
+msgstr "Jeu inconnu."
+
+#: app/validators.py:789
+msgid "Invalid start date format."
+msgstr "Format de date de début invalide."
+
+#: app/validators.py:790
+msgid "A start date is required."
+msgstr "Une date de début est requise."
+
+#: app/validators.py:796
+msgid "Invalid end date format."
+msgstr "Format de date de fin invalide."
+
+#: app/validators.py:804
+msgid "A tryout must allow at least one player."
+msgstr "Une sélection doit accepter au moins un joueur."
+
+#: app/validators.py:807
+msgid "The player limit must be a whole number."
+msgstr "La limite de joueurs doit être un nombre entier."
+
+#: app/validators.py:819
+msgid "End date cannot be before start date."
+msgstr "La date de fin ne peut pas précéder la date de début."
+
+#: app/validators.py:846 app/validators.py:847
+msgid "Team name is required."
+msgstr "Le nom de l’équipe est obligatoire."
+
+#: app/validators.py:871
 msgid "Scores run from 1 to 10."
 msgstr "Les notes vont de 1 à 10."
 
-#: app/validators.py:816
+#: app/validators.py:872
 msgid "A score must be a whole number from 1 to 10."
 msgstr "Une note doit être un nombre entier de 1 à 10."
 
@@ -313,12 +321,12 @@ msgstr "Évaluation enregistrée."
 msgid "Evaluation updated!"
 msgstr "Évaluation mise à jour."
 
-#: app/routes/evaluations.py:210 app/routes/teams.py:305
-#: app/routes/teams.py:346 app/routes/teams.py:387 app/routes/teams.py:412
-#: app/routes/teams.py:437 app/routes/teams.py:472 app/routes/tryouts.py:437
-#: app/routes/tryouts.py:453 app/routes/tryouts.py:473
-#: app/routes/tryouts.py:512 app/routes/tryouts.py:548
-#: app/routes/tryouts.py:567
+#: app/routes/evaluations.py:210 app/routes/teams.py:341
+#: app/routes/teams.py:384 app/routes/teams.py:427 app/routes/teams.py:455
+#: app/routes/teams.py:483 app/routes/teams.py:520 app/routes/tryouts.py:444
+#: app/routes/tryouts.py:460 app/routes/tryouts.py:480
+#: app/routes/tryouts.py:519 app/routes/tryouts.py:555
+#: app/routes/tryouts.py:574
 msgid "Permission denied."
 msgstr "Accès refusé."
 
@@ -377,130 +385,130 @@ msgstr "Utilisez « Mon ou mes équipes » pour consulter vos équipes."
 msgid "You do not have permission to view teams."
 msgstr "Vous n’avez pas les droits pour consulter les équipes."
 
-#: app/routes/teams.py:74
+#: app/routes/teams.py:79
 msgid "This page is for players."
 msgstr "Cette page est réservée aux joueurs."
 
-#: app/routes/teams.py:150
+#: app/routes/teams.py:186
 msgid "You do not have permission to create teams."
 msgstr "Vous n’avez pas les droits pour créer une équipe."
 
-#: app/routes/teams.py:161 app/routes/teams.py:203
+#: app/routes/teams.py:197 app/routes/teams.py:239
 #, python-format
 msgid "Team \"%(name)s\" already exists."
 msgstr "L’équipe « %(name)s » existe déjà."
 
-#: app/routes/teams.py:182
+#: app/routes/teams.py:218
 #, python-format
 msgid "Team \"%(name)s\" created successfully!"
 msgstr "Équipe « %(name)s » créée."
 
-#: app/routes/teams.py:192
+#: app/routes/teams.py:228
 msgid "You do not have permission to edit this team."
 msgstr "Vous n’avez pas les droits pour modifier cette équipe."
 
-#: app/routes/teams.py:236
+#: app/routes/teams.py:272
 #, python-format
 msgid "Team \"%(name)s\" updated successfully!"
 msgstr "Équipe « %(name)s » mise à jour."
 
-#: app/routes/teams.py:264
+#: app/routes/teams.py:300
 msgid "You do not have permission to delete teams."
 msgstr "Vous n’avez pas les droits pour supprimer une équipe."
 
-#: app/routes/teams.py:295
+#: app/routes/teams.py:331
 #, python-format
 msgid "Team \"%(name)s\" deleted successfully."
 msgstr "Équipe « %(name)s » supprimée."
 
-#: app/routes/teams.py:310
+#: app/routes/teams.py:348
 msgid "Please select a coach."
 msgstr "Veuillez choisir un coach."
 
-#: app/routes/teams.py:315
+#: app/routes/teams.py:353
 msgid "Only coaches can be assigned as coach."
 msgstr "Seuls les coachs peuvent être assignés comme coach."
 
-#: app/routes/teams.py:321
+#: app/routes/teams.py:359
 #, python-format
 msgid "%(username)s is already a coach of %(name)s."
 msgstr "%(username)s est déjà coach de %(name)s."
 
-#: app/routes/teams.py:334
+#: app/routes/teams.py:372
 #, python-format
 msgid "%(username)s added as coach of %(name)s."
 msgstr "%(username)s a été ajouté comme coach de %(name)s."
 
-#: app/routes/teams.py:351
+#: app/routes/teams.py:391
 msgid "Please select a manager."
 msgstr "Veuillez choisir un gérant."
 
-#: app/routes/teams.py:356
+#: app/routes/teams.py:396
 msgid "Only managers can be assigned as manager."
 msgstr "Seuls les gérants peuvent être assignés comme gérant."
 
-#: app/routes/teams.py:362
+#: app/routes/teams.py:402
 #, python-format
 msgid "%(username)s is already a manager of %(name)s."
 msgstr "%(username)s est déjà gérant de %(name)s."
 
-#: app/routes/teams.py:375
+#: app/routes/teams.py:415
 #, python-format
 msgid "%(username)s added as manager of %(name)s."
 msgstr "%(username)s a été ajouté comme gérant de %(name)s."
 
-#: app/routes/teams.py:402
+#: app/routes/teams.py:445
 #, python-format
 msgid "Coach removed from %(name)s."
 msgstr "Coach retiré de %(name)s."
 
-#: app/routes/teams.py:427
+#: app/routes/teams.py:473
 #, python-format
 msgid "Manager removed from %(name)s."
 msgstr "Gérant retiré de %(name)s."
 
-#: app/routes/teams.py:443 app/routes/tryouts.py:477 app/routes/tryouts.py:578
+#: app/routes/teams.py:490 app/routes/tryouts.py:484 app/routes/tryouts.py:585
 msgid "Please select a player."
 msgstr "Veuillez choisir un joueur."
 
-#: app/routes/teams.py:448
+#: app/routes/teams.py:496
 msgid "Can only assign players to teams."
 msgstr "Seuls des joueurs peuvent être assignés à une équipe."
 
-#: app/routes/teams.py:454
+#: app/routes/teams.py:502
 #, python-format
 msgid "%(username)s is already on %(name)s."
 msgstr "%(username)s fait déjà partie de %(name)s."
 
-#: app/routes/teams.py:462
+#: app/routes/teams.py:510
 #, python-format
 msgid "%(username)s added to %(name)s!"
 msgstr "%(username)s a été ajouté à %(name)s."
 
-#: app/routes/teams.py:479 app/routes/teams.py:553
+#: app/routes/teams.py:527 app/routes/teams.py:601
 #, python-format
 msgid "%(username)s is not on %(name)s."
 msgstr "%(username)s ne fait pas partie de %(name)s."
 
-#: app/routes/teams.py:487
+#: app/routes/teams.py:535
 #, python-format
 msgid "%(username)s removed from %(name)s."
 msgstr "%(username)s a été retiré de %(name)s."
 
-#: app/routes/teams.py:524 app/routes/teams.py:542
+#: app/routes/teams.py:572 app/routes/teams.py:590
 msgid "You do not have permission to add notes to this team."
 msgstr "Vous n’avez pas les droits pour ajouter des notes à cette équipe."
 
-#: app/routes/teams.py:532
+#: app/routes/teams.py:580
 msgid "Team notes added successfully!"
 msgstr "Notes d’équipe ajoutées."
 
-#: app/routes/teams.py:547 app/routes/users/notes.py:207
+#: app/routes/teams.py:595 app/routes/users/notes.py:207
 #: app/routes/users/notes.py:250
 msgid "Can only add notes for players."
 msgstr "Il n’est possible d’ajouter des notes que pour des joueurs."
 
-#: app/routes/teams.py:563
+#: app/routes/teams.py:611
 #, python-format
 msgid "Note added for %(username)s!"
 msgstr "Note ajoutée pour %(username)s."
@@ -529,76 +537,76 @@ msgstr "Sélection mise à jour."
 msgid "You do not have permission to view this tryout."
 msgstr "Vous n’avez pas les droits pour consulter cette sélection."
 
-#: app/routes/tryouts.py:404
+#: app/routes/tryouts.py:411
 msgid "Only players can register for tryouts."
 msgstr "Seuls les joueurs peuvent s’inscrire à une sélection."
 
-#: app/routes/tryouts.py:408
+#: app/routes/tryouts.py:415
 msgid "This tryout is not accepting registrations."
 msgstr "Cette sélection n’accepte pas d’inscriptions."
 
-#: app/routes/tryouts.py:415
+#: app/routes/tryouts.py:422
 msgid "You are already registered for this tryout."
 msgstr "Vous êtes déjà inscrit à cette sélection."
 
-#: app/routes/tryouts.py:421 app/routes/tryouts.py:496
+#: app/routes/tryouts.py:428 app/routes/tryouts.py:503
 msgid "This tryout is full."
 msgstr "Cette sélection est complète."
 
-#: app/routes/tryouts.py:427
+#: app/routes/tryouts.py:434
 msgid "Successfully registered for tryout!"
 msgstr "Inscription à la sélection réussie."
 
-#: app/routes/tryouts.py:443
+#: app/routes/tryouts.py:450
 #, python-format
 msgid "Tryout status updated to %(new_status)s."
 msgstr "Statut de la sélection mis à jour : %(new_status)s."
 
-#: app/routes/tryouts.py:463
+#: app/routes/tryouts.py:470
 msgid "Registration status updated."
 msgstr "Statut d’inscription mis à jour."
 
-#: app/routes/tryouts.py:482
+#: app/routes/tryouts.py:489
 msgid "Can only register players."
 msgstr "Seuls des joueurs peuvent être inscrits."
 
-#: app/routes/tryouts.py:488
+#: app/routes/tryouts.py:495
 #, python-format
 msgid "%(username)s is already registered for this tryout."
 msgstr "%(username)s est déjà inscrit à cette sélection."
 
-#: app/routes/tryouts.py:502
+#: app/routes/tryouts.py:509
 #, python-format
 msgid "%(username)s registered for tryout!"
 msgstr "%(username)s est inscrit à la sélection."
 
-#: app/routes/tryouts.py:538
+#: app/routes/tryouts.py:545
 #, python-format
 msgid "%(username)s removed from tryout."
 msgstr "%(username)s a été retiré de la sélection."
 
-#: app/routes/tryouts.py:556
+#: app/routes/tryouts.py:563
 #, python-format
 msgid "Team \"%(team_name)s\" created!"
 msgstr "Équipe « %(team_name)s » créée."
 
-#: app/routes/tryouts.py:587
+#: app/routes/tryouts.py:594
 msgid "That player is not registered for this tryout."
 msgstr "Ce joueur n’est pas inscrit à cette sélection."
 
-#: app/routes/tryouts.py:593
+#: app/routes/tryouts.py:600
 msgid "Player is already on this team."
 msgstr "Ce joueur est déjà dans cette équipe."
 
-#: app/routes/tryouts.py:598
+#: app/routes/tryouts.py:605
 msgid "Player added to team!"
 msgstr "Joueur ajouté à l’équipe."
 
-#: app/routes/tryouts.py:608
+#: app/routes/tryouts.py:615
 msgid "You do not have permission to delete this tryout."
 msgstr "Vous n’avez pas les droits pour supprimer cette sélection."
 
-#: app/routes/tryouts.py:644
+#: app/routes/tryouts.py:651
 msgid "Tryout deleted successfully."
 msgstr "Sélection supprimée."
 
diff --git a/app/validators.py b/app/validators.py
index 2b6738f..230773b 100644
--- a/app/validators.py
+++ b/app/validators.py
@@ -460,6 +460,62 @@ class UploadContractSchema(StripMixin):
     )
 
 
+#: Where a player stands on a team roster.
+#:
+#: `TeamPlayer.status` is a NOT NULL String(20) that `add_player` filled from
+#: `request.form.get('status', 'starter')` with no check at all, so a forged
+#: submission stored any string it liked. It then survived until someone
+#: pressed the toggle, which reads `'substitute' if status == 'starter' else
+#: 'starter'` — so an unknown value silently became `starter`, i.e. promoted
+#: whoever held it (SEC-16).
+TEAM_PLAYER_STATUSES = ('starter', 'substitute')
+
+
+class TeamStaffSchema(StripMixin):
+    """One staff id, posted by the add/remove coach and manager forms.
+
+    Both ids are optional here even though each route needs exactly one:
+    `remove_coach` treats an absent id as "remove every coach", and the add
+    routes already carry their own translated "Please select a coach."
+    message. Making the field required would replace that message with a
+    generic one for no gain.
+
+    What this schema is for is the conversion. Wave K closed `create_team`
+    and `edit_team` and left five sibling routes reading `int(...)` straight
+    off the form — a non-numeric id was a 500 in each. Fixing a pattern in
+    one place and not its neighbours is the mistake this project keeps
+    making; this is the same mistake, made by the fix for it.
+    """
+
+    coach_id = fields.Integer(
+        allow_none=True,
+        load_default=None,
+        validate=validate.Range(min=1),
+        error_messages={'invalid': _l('Invalid coach selection.')},
+    )
+    manager_id = fields.Integer(
+        allow_none=True,
+        load_default=None,
+        validate=validate.Range(min=1),
+        error_messages={'invalid': _l('Invalid manager selection.')},
+    )
+
+
+class TeamPlayerSchema(StripMixin):
+    """A player being put on a team roster, and where they stand on it."""
+
+    player_id = fields.Integer(
+        allow_none=True,
+        load_default=None,
+        validate=validate.Range(min=1),
+        error_messages={'invalid': _l('Invalid player selection.')},
+    )
+    status = fields.String(
+        load_default='starter',
+        validate=validate.OneOf(TEAM_PLAYER_STATUSES, error=_l('Unknown roster status.')),
+    )
+
+
 class OneOnOneRequestSchema(StripMixin):
     """A player asking their coach for a session (MNT-12).
 
diff --git a/tests/test_authorization.py b/tests/test_authorization.py
index 3b9fcd3..af2cade 100644
--- a/tests/test_authorization.py
+++ b/tests/test_authorization.py
@@ -583,3 +583,148 @@ class TestTeamStaffAssignment:
         assert response.status_code < 500
         with app.app_context():
             assert OrgTeam.query.count() == 0
+
+
+class TestTeamRosterAssignment:
+    """SEC-16, the half wave K missed.
+
+    Wave K put a schema on `create_team` and `edit_team` and left five
+    sibling routes reading `int(request.form.get(...))` — `add_coach`,
+    `add_manager`, `remove_coach`, `remove_manager` and `add_player`. Each
+    was a 500 on a non-numeric id. `add_player` also accepted any `status`
+    string into a NOT NULL column, and none of them checked whether the
+    account had been deactivated.
+
+    Fixing a pattern in one place and not its neighbours is the mistake this
+    project keeps making. Here it was made by the fix for it.
+    """
+
+    @pytest.fixture
+    def team(self, app, make_user):
+        from app.models import OrgTeam
+
+        admin_id = make_user('admin')
+        with app.app_context():
+            org_team = OrgTeam(name='Varsity', created_by=admin_id)
+            db.session.add(org_team)
+            db.session.commit()
+            return org_team.id
+
+    @pytest.mark.parametrize(
+        ('path', 'field'),
+        [
+            ('add_coach', 'coach_id'),
+            ('add_manager', 'manager_id'),
+            ('remove_coach', 'coach_id'),
+            ('remove_manager', 'manager_id'),
+            ('add_player', 'player_id'),
+        ],
+    )
+    def test_a_non_numeric_id_is_not_a_500(self, app, client, team, as_role, path, field):
+        as_role('admin')
+
+        response = client.post(f'/teams/{team}/{path}', data={field: 'not-a-number'})
+
+        assert response.status_code < 500
+
+    def test_a_real_coach_is_added(self, app, client, team, as_role, make_user):
+        """The premise for the two tests below."""
+        from app.models import OrgTeam
+
+        coach_id = make_user('coach')
+        as_role('admin')
+
+        client.post(f'/teams/{team}/add_coach', data={'coach_id': str(coach_id)})
+
+        with app.app_context():
+            org_team = db.session.get(OrgTeam, team)
+            assert [c.id for c in org_team.coaches.all()] == [coach_id]
+
+    def test_a_player_cannot_be_added_as_coach(self, app, client, team, as_role, make_user):
+        from app.models import OrgTeam
+
+        player_id = make_user('player')
+        as_role('admin')
+
+        client.post(f'/teams/{team}/add_coach', data={'coach_id': str(player_id)})
+
+        with app.app_context():
+            assert db.session.get(OrgTeam, team).coaches.all() == []
+
+    def test_a_deactivated_coach_cannot_be_added(self, app, client, team, as_role, make_user):
+        """`is_active_account` is what says the person has left the club.
+        Putting them back on a roster contradicts it."""
+        from app.models import OrgTeam, User
+
+        coach_id = make_user('coach')
+        with app.app_context():
+            db.session.get(User, coach_id).is_active_account = False
+            db.session.commit()
+        as_role('admin')
+
+        client.post(f'/teams/{team}/add_coach', data={'coach_id': str(coach_id)})
+
+        with app.app_context():
+            assert db.session.get(OrgTeam, team).coaches.all() == []
+
+    def test_a_deactivated_player_cannot_be_added(self, app, client, team, as_role, make_user):
+        from app.models import TeamPlayer, User
+
+        player_id = make_user('player')
+        with app.app_context():
+            db.session.get(User, player_id).is_active_account = False
+            db.session.commit()
+        as_role('admin')
+
+        client.post(f'/teams/{team}/add_player', data={'player_id': str(player_id)})
+
+        with app.app_context():
+            assert TeamPlayer.query.filter_by(org_team_id=team).count() == 0
+
+    def test_a_deactivated_player_is_not_offered(self, app, client, as_role, make_user):
+        """The select and the route agreed on nothing: the query had no
+        is_active_account filter while the two beside it did."""
+        from app.models import User
+
+        player_id = make_user('player', username='ghostplayer')
+        with app.app_context():
+            db.session.get(User, player_id).is_active_account = False
+            db.session.commit()
+        as_role('admin')
+
+        body = client.get('/teams').get_data(as_text=True)
+
+        assert 'ghostplayer' not in body
+
+    def test_an_unknown_roster_status_is_refused(self, app, client, team, as_role, make_user):
+        """`status` went into a NOT NULL String(20) unchecked, and the toggle
+        reads anything that is not 'starter' as substitute — so an unknown
+        value silently promoted its holder on the next press."""
+        from app.models import TeamPlayer
+
+        player_id = make_user('player')
+        as_role('admin')
+
+        client.post(
+            f'/teams/{team}/add_player',
+            data={'player_id': str(player_id), 'status': 'captain-for-life'},
+        )
+
+        with app.app_context():
+            rows = TeamPlayer.query.filter_by(org_team_id=team).all()
+            assert [r.status for r in rows] != ['captain-for-life']
+
+    def test_a_known_status_is_kept(self, app, client, team, as_role, make_user):
+        from app.models import TeamPlayer
+
+        player_id = make_user('player')
+        as_role('admin')
+
+        client.post(
+            f'/teams/{team}/add_player',
+            data={'player_id': str(player_id), 'status': 'substitute'},
+        )
+
+        with app.app_context():
+            row = TeamPlayer.query.filter_by(org_team_id=team).one()
+            assert row.status == 'substitute'