Can a player who has entered the game as a courtesy runner only later sub in for another player?

Answer 1

On defense, a courtesy runner can sub for any position they want the next half inning thy play (if the coach wants) or just come out of the game. They can't, however, sub in again as a courtesy runner, and if taken out of the game from pinch running (not DH or playing a defensive position) they can't come back into the game.