Well, it's not something you would want to throw JD into out of the blue in the middle of the season. He could be taking grounders during the off season. Let him take reps at 1B throughout spring training and throughout the season. Cora is the master of selling these types of changes to the players, so I'm sure JD would be fully on board.
Just because JD wouldn't be needed to play 1B, that doesn't mean he can't play there periodically throughout the season. He could play there to give Moreland or Pearce a rest, where one of them could be the DH.
I think it makes a lot of sense.