I know a lot of folks want this to happen but it is looking less and less likely, especially for PP.  He still has something left, and likely will even after next year.  I don't see DA resigning him for reason of nostalgia, so basically if PP doesn't want to retire next year, then he will play somewhere else.

Not to mention that DA could trade PP this summer.

As for KG, I know he is a prideful guy.  And I know he has made a lot of money over his career.  But, as much as people believe it, I don't see him leaving money on the table and retiring before the contract is over.  And I agree that he is tied to PP in a big way.  If PP is gone, and KG doesn't retire (like I predict), then KG will play elsewhere as well.

To put simply, we are reaching the point where both players would be an albatross to the Celts getting better and moving forward.  I believe they each will want to continue playing and will do so.