The game is called football manager. If you want to act as a player/manager, I believe that there is or was a game series that featured exactly on that.
There is not a single thing this feature would add. For the same reason, you can't do the stadium upgrades yourself, simulate your private life (play the Sims instead!) or drive a car to work and home in the game.
Like it was mentioned a lot of times before - the game does not intend to simulate all aspects and possibilities of the real world. Players don't get shot in Colombia, there is no matchfixing (would you really like that included?), you don't have players get banned for lifetime for drug abuse.
Would you really enjoy it, if you would win a European cup final and have it taken away for you because the game decided that one of your fans had thrown a grenade into the other fan block? Or maybe another Heysel tragedy?
It's a game. And LLM is about playing the game in a realistic fashion that the game allows. There are dozens of things where the programming and designing work would be better put in.