The thing is that Lattimore will be 29 next year and isn't going to want to stay here for a rebuild which is what is going to happen. So, you either trade him now at the height of his value, keep him until he demands a trade in the offseason and tanks his value because he wants to play for a ring, or lose him the year after when he leaves in free agency for nothing. Personally, I think the correct move is to trade him at the height of his value.