I managed to do it by playing Ohtani in the outfield and then having him switch positions with the pitcher, who I then subbed out for another outfielder. It let me use him for one inning, then it said "position player on the mound" and made me either take him out or put him in the outfield again. He was really good for that one inning, though. Still has all of his pitches, including the 100 mph fastball.
InsolublePancak_XBL
@InsolublePancak_XBL