For how long this period of maximum 3 injuries lasts?
This must be permanent. In real football the clubs have a roster of 25-35 players but here we can't and we cannot demand it because there must be some limits in the program I guess. That's why I suggest this.
It's not logic a team of 22 players having 5 injured players like in your case.
This also gives a big advantage to T buyers/farmers who can replace or heal their injured players.

A fb app , a pc game like this can't be a simulation of real football but still can use some rules or program actions which can follow some logic.
Also because actually it's a management/strategy/coaching game, must have rules so the player understand how to play it and how to improve himself.