I don't think anyone cares about displacing Redding, its more a matter of forcing a choice between Perez and Livan (and the new guy) down the road. Now if "down the road" means September (they think Perez will be out awhile longer) then maybe you do that, but if they expect Perez back any time soon I don't think they can. The Red Sox have like 8 starting pitchers who could legitimately be in a MLB rotation, and they're content to leave Bucholtz dominating AAA despite obviously being ready for the majors, the Mets were not content sending down a less-ready-than-Bucholtz Omir Santos, prefering to trade away their depth rather than resolve the conflict by asking the question "who has options?" as the Sox have in keeping the obviously inferior, but not useless, Brad Penny pitching over Bucholtz. I'm not sure the Mets can make that kind of decision (weakening the current club slightly in order to keep options and depth around down the road), and if not then they can't acquire a veteran (read: no options) starter for Church.