Doc's not awful by any means (I'd say he's one of the better coaches in the league) but he can be stubborn with rotations.
I'm all for waiting until seeing what Perk can give us before saying "Oh, Shaq should be in the starting lineup" or "oh, Perk should be in the starting lineup". The problem is, I'm not too confidant Doc will be that flexible.
Based on his past, it seems very likely that Perk is going back into the starting lineup regardless of what happens. I don't like that sort of predetermination.