ainge has been so successful because he buys low and sells high (al jefferson, antoine walker, ricky davis, etc). tony's stock couldn't be much lower right now. aside from that dunk, there are still serious questions about his health. even when he had solid stretches of play during the season, he usually regressed soon after, and at times looked terrible.
point being, we can't get anything for him in a sign and trade, and we can probably re-sign him for VERY cheap. i mean what leverage would his agent have in negotiations?
think about it: IF tony returns to how he played before his injury in january of '07, we have the potential to be almost unbeatable. especially as pierce and ray allen get older, having a young, developing swingman of that caliber off the bench can save the vets' legs and help bridge the gap between the "big three" era and the next era.
his stock can't drop much lower, but it certainly can skyrocket next season. no reason not to re-sign him, unless you really think he has no chance of returning to his old self.