Ukbrotha
Superstar
In these cases it's usually lack of professionalism or drinking/drugs. Pogba's never been caught doing anything crazy other than those balloons so my guess is it's former.
Besides meniscus it's always muscle injuries with him, this new injury is to his adductor from taking free kicks. That means he doesn't take his training and rehab seriously. Even on rare occasions when he's not injured for an extended period of time he's still lacking stamina, all signs point to him being unprofessional.
Just glad he's someone else's problem now.