Pretty simple math. Richt knew that Thomas would be gone for the first game (or more?) this fall before he made the decision to move Richard Samuel back to that side of the ball. With zero carries between the other backs left eligible for week one it was a no brainer to have Samuel move back to offense. Samuel, Crowell and Malcome will all three get a chance to show what they can do in week one. I suspect Crowell will get the first carry, then every back will get their shot. As the game goes on each will be given the chance to show they deserve the most carries. With back to back games against top ten teams they will all be given plenty of chances to show what they can do.
As a side note is it any wonder that some of the top backs for future classes (2013, 2014) are committing to UGA so early, the chance to come in and play right away will clearly be there.