It's a tough break for us C's fans. While there is little to no chance of a deep playoff run now, I really don't want to see Pierce or KG playing somewhere else to end their careers.
If they agree to it and Ainge can genuinely get something to help the team rebuild then okay, but I'm not really sure there's a big market for guys over 35 with big contracts and declining abilities.
Knowing the competitive spirit those two have, I think they will be keen to play out this season to see how successful they can be against the odds.
I think the best scenario would be if they can go out with an honourable 2nd round exit and retire in the offseason.
Then Ainge can build around Bradley, Sullinger, Green and Melo next season, with Rondo to return late in the piece. Get those young guys plenty of playing time, hopefully get a decent amount of ping pong balls for the 2014 draft and see if they can land a decent FA.