Well, I could see them both coming back for 2012-2013 for one last chance. And it wouldn't be a bad thing, either. That'd mean by the summer of 2013, KG and Ray would be off the books and PP would only have one year left.
The only reason not to do that would be if Danny is convinced he can nab a top free agent in 2012. However, if the NBA is serious about lowering the cap and reducing salary, our chances are probably even smaller, as Pierce and Rondo will already put them at 27-28 million themselves.