I'd like to clarify something.
In your case, your player is substituted out during the 3rd quarter.
Based on the game manual (The Game Engine part), the player wouldn't become exhausted at that point.
What I mean is that we can't rule out the possibility that the coach's decision might be related to whether the player could become exhausted.
But I'm not sure whether that is actually the reason.
What I'm curios is whether stamina affects the time when this multiplayer come into play, or it is independent.
My player with stamina 7 got exhausted at .7 (min 34). Does a player with stamina 8 reaches exhaustion at min 38.5?
Sorry, I don't know.