According to MLB rules...
Assume you start the game with the Ohtani rule (same player is DH/Starting Pitcher) which we'll call Player A. Later in the game, another player comes off the bench to pitch but Player A remains as the DH.
Can that player, Player A the DH, then come back in to pitch or play a defensive position again later in the game?
References to actual MLB rules would be helpful, thanks!