The Game Injured Playing A Game

TMZ has learned ... Game broke a bone in his thumb and his wrist during a playoff game in the famous Drew League in Los Angeles.

According to our sources, Game fell after a slam dunk ... and while he was on the ground, somebody accidentally stomped on his right hand ... crushing the bones.

It's possible the bone-breaker was a celebrity -- Game's team features a bunch of NBA stars including DeMar DeRozan, Paul George, John Wall and Metta World Peace.