Kelly’s a good option; solid in all facets of the game.
He would immediately fill the role Gallinari would have and form a rotation that is 9 deep, ready and battle tested for the playoffs.
Gallo is rehabbing and might not be his usual self even if he does return this season, Payton will get benched as soon as the Smart/Brown/Brogdon/White rotation is healthy and available, and Kelly is a big, healthy, strong, durable, and versatile addition to the playoff rotation.
I prefer to go in a different direction without giving up Gallo+Pritchard (trading a future protected 1st or 2nds and save Payton for another transaction after the season), but despite my preference, I know that Kelly would help us along the way to win the Championship.