First and foremost, if this is a question of Ray staying and starting or Ray leaving, this discussion should end now. We're talking about the first 5-6 minutes of the game. After that, Doc can adjust his rotations however he sees fit.
Second of all, I think the perceived change that Bradley brought to the starting unit was only partly his doing.
Don't get me wrong. I like Bradley and I like him a lot. I think he has star potential.
However, at the time he was breaking into the starting unit, other things began to happen that had nothing to do with Bradley.
First and foremost, KG started to turn it around and have his own personal renaissance. Second, PP finally got his butt into shape after the lockout.
On top of this, when Ray came back, he was Ray with bone spurs, making Bradley look even better. That should change next year.
Might the Celtics be better with Bradley starting? Sure. But I don't think this nearly as dramatic of an issue as people are making it out to be. I also think Bradley and Green could make an incredible 6th man duo off the bench, coming in midway through the 1st and bringing a huge boost of injury to run with Rondo the rest of the quarter.
And after that, who started and who came off the bench is really inconsequential.