I don't mean to speak for the OP, but I would think that he meant - after their contracts are up.
I have a feeling that Pierce will be at least a $5m player the summer of 2014, assuming the Cs don't make him a FA this summer.
If he gets cut loose this summer and hits the market for the 2014 season, I don't know why a team close to a title like OKC or Brooklyn, wouldn't throw at least a MLE deal at him to be a Manu-style 6th man.
However, if the Cs are title contenders when PP hits free agency again, and he's feeling benevolent, it would be wonderful if he played for the vetmin if that meant the Cs could use salary cap room for a player or two to put the team over the top.
The last future HOFer to play for the vetmin was Shaq here in Boston. Unfortunately, it didn't work out due to his injuries, but good players signing value contracts are important to championship caliber teams (Miami with battier and RA at $3m per, for example), and certainly will be even more important in the future with this new CBA and the draconian luxtax penalties.
If PP and KG want to ring chase with Boston in their golden years for chump change, I'm all for it, but I don't see that happening. Pro athletes, especially the stars, expect to get compensated for their services. And that's the way it should be.