It's a tough dilemma. We are tremendously dependent on Rondo and Pierce to generate shots for the rest of the team. Take any of our players (other than maybe KG) away from those two, and they will struggle to score.
This goes for all of our 2-guard options: Ray, Pietrus, Bradley and Dooling.
So the key is measuring how much you lose offensively/gain defensively by putting one of those 2-guard options in the cozy spot between Rondo and Pierce.
With Bradley there, we get our best defensive option against teams that like to play quick combo guards at the starting 2-spot. But we lose a 3-point shooter offensively (a great one in Ray, a good one in Pietrus), and we become extra vulnerable to 2-guards with size (I am very interested to see how Bradley does against Wade, though - if he does well in that match-up, it might be worth starting him when we play Miami). Nor do we gain any rebounding as Bradley's a poor rebounder.
Pietrus is the guy you want starting over Ray. He's a better wing defender than Ray or Bradley. He keeps a 3-point shooter on the floor. He can rebound at a good rate for a 2-guard.
Unfortunately, with Pietrus sidelined for the interim, our best option is off the table for now.
I am hoping that Bradley can start to take and make more of those corner 3s. If he can start making those @ 35%, he becomes a lot more appealing as a starter.