I live in Tampa and watched Jon Gruden literally run Cadillac Williams out of the league. Dude was just spent and if I remember correctly wasn't the biggest or healthiest coming out of Auburn.
I can understand wanting to be "the man" BUT if I'm a RB with pro potential, I don't want anything to do with 25-30 carries a game in college. Put me in a position to win with a great balanced team. Highlight me with carries, catches out of the backfield, and my developing blocking ability, but please leave me something in the tank.
Particularly with the possibility of 15 game seasons, I'd want nothing with a GA or Alabama and the increased risk of breaking down.