If a player is truly DTD then don't DL him. If he is butera or some other bench player, then DL them if they are going to miss even a few days. Since they are so close to replacement level, when if they play at 90% that provide basically the same value as a tripple a player. With a starter, I would say if they are going to miss at least 7-10 games, I would rather DL them and have them get fully healthy and rested. Span was a unique case because avoiding the DL might have helped his trade value slightly