I think that the Celtics will try and unload Terry if they have to take on a bad contract like Perk. Something like KG and Terry for Perk, Lamb, a first and the Maynor trade exception (although I can't add the trade exception on the trade machine, so maybe its not even possible.)
This is a lot to give up for OKC, but it just might be a move that could get them a championship. For Boston, it provides them a lot of ammo to jumpstart the rebuilding process. If the Celtics decide they want to build around Rondo, bringing back Perk would be a good step.