Not good at all, neither is the question.
No player has to beg out of a game. The team doctor and trainer make that call. Athletes, ALL no matter what sport, what conference are encouraged to report issues. Players don't have to fake anything if they need a rest. Most coaches pick up on it anyway.
You should use your sons situation to understand what happens when you don't take care of injuries. The sooner it's addressed, the sooner the player is back on the field.
I am really surprised at you.
It's just a making conversation question. Totally agree that injuries need to be addressed and not ignored. That said, what it a player had a slight fever (99.7?) or had the runs or had a really bad sore throat? Something that a motrin or imodium could address? Yet, the player instead told the coach "I have to sit out today." Is that a mark against the player?
(BTW @GoingwiththePitch book made me think of the question because there was one time he was very sick with fever and stomach issues but he still played in the game.)