If I had to give percentages on probability by QB, I would say:
Rozier - 51
Allison - 30
Weldon - 10
Perry - 8
Others - 1
So I'm giving Rozier a better than 50% chance of being the starting quarterback with Allison also having a decent chance. I think Weldon has a better chance among the true freshman and Perry, simply because he's going to be here a lot earlier and had the opportunity to participate in many more practices both formal and informal it. But not much that greater than Perry.
Of course, like everyone else, these are just guesses and anything could happen. We might know more after spring practice and make better predictions then. But even then, I don't think we're going to have a good idea till mid to late summer just who the starter will be, this could even stretch out right into the week before the first game.