As we know, when a player gets injured, he leaves the game. Sometimes, he even has a lengthy stay on the injured list.
I would like to see a scenario where a player gets hurt, during the game, but then later returns to play. It may be only a temporary injury, such as an elbow in the head requiring stitches, a sprained ankle, or bloody nose.
It can change the game, but still allow the player to return to participate.