If Zebina plays well, which I think he can with Thuram and Cannavaro in central defence, or even better, Tudor can stay healthy and show the form that he's been displaying recently, but show it on a consistent basis, then Juve will be fine.
That could move Thuram back to RB, if he so chooses, and it will allow you to have some legitimate depth with Legro, Ferrara, Montero, et al....as your backups.
I just don't want to go into the season depending on Birindelli to play RB on a full time basis. If Zebina fails miserably,and Tudor gets hurt again, then we could have a problem