If Amir can get his mojo back the defence can improve even more. I think there are signs. With all the trade talks around bigs and two young guys in the wings doing well, this is a very important time for his career. He needs to prove he has more than just holding a spot until something happens.
Ultimately that could be what he is doing (holding a spot). If one of the hyped trades fro a younger big occurs, then Amir may not get on the floor with everybody fit.