Could easily see Perk leaving after this season. MIA would be a place willing to give him the MLE, especially if they get chewed up by ORL in the post season. Crunch time 5 of Perk, Bosh, M. Miller, Wade, and LJ.
Can't see the Celts loving the idea of an MLE contract for 3 or 4 years.
Perk will get at least $8M/year. C's would happily match a MLE type contract. Look around the league at what starting or decent backup centers get. For example, Gortat, who plays about half the minutes as Perk, got the full MLE.
The Cs can keep Perk if they want to keep him. The only way they lose him is if some team with cap space signs him to a huge front loaded contract that the Cs don't want to match. Miami won't be able to do that.