Baseball:
If your player started the game, the selection will stand, regardless of whether you took the Over or the Under. This includes circumstances where the player leaves due to injury, ejection, or substitution.
Football and Basketball:
In general, if your player played in the game, then the selection will stand. The only exception is if your player is injured in the 1st half of the game, leaves the game, and does not return. In that case, your full-game selection will be protected.
All Other Sports:
As long as your player played in the game, your selection will be graded, regardless of whether you took the Over or the Under. This includes circumstances where the player leaves due to injury, ejection, or substitution.