I was wondering when someone would bring up this trade.
Ainge was coming of his first and only All-Star season, but had been demoted to the bench in favor of Brian Shaw. Like Perkins this year, Ainge back then was the only player on the team who had the right contract situation to be part of a trade where you give up value to get value. At 29, he was still in his prime. Unlike this year, people understood this fact and trade rumors had surrounded Ainge for a while. In 2011, I'd argue the Celtics had three players who other teams might return more than the players were worth: Perkins, Erden, and Bradley.
With Bird injured, Ainge was pretty much the only real perimeter threat on the team, but they were getting back two former top ten draft picks.
With Bird's injured heel that season, the Celtics were not real contenders and were putting a lot of stress on McHale and Parish. Had Bird not injured his back in a charity game playing against Jordan, perhaps the move would have preserved the Big Three enough to ride them to at least one more strong last run at the title. Had McHale not been a base-year compensation guy, maybe Red would have found a way to turn him into a younger big to team with Bird, Parish, Lewis, Ainge, and Shaw. Hearing that Boston supposedly could have moved McHale for Detlef Schrempf and Sam Perkins makes you wonder "what if".
I've read that McHale was very angry about the trade and I would love for some reporter to get his take on the Celtics lockerroom after Ainge was traded. Reportedly, Ainge was a mediator who could provide some balance when Bird and McHale clashed behind the scenes, so I can see how his departure could affect team chemistry.