That's a tough choice. I wouldn't drop any of your starters, but Stewart vs. Julio or Escobar, for instance, is a hard decision. Stewart's looked good of late, but he may not get every single save opportunity. He should definitely be picked up in a ten team league, though. The best scenario would be to trade one of your current relievers plus a bat for a hitting upgrade, and then pick up Stewart, but that may not be viable. Of course, if you have a bench hitter you can drop in order to grab Stewart, that would be good, too. If it comes down to dropping a pitcher, however, I'd probably wait just a little longer before making such a move.