because with such a significant injury, he probably needs that solid year to prove his potential to NFL teams. I can't imagine that he doesn't have NFL aspirations, and that that was his plan in transferring to BYU, since he hadn't necessarily been able to prove that potential thus far with the PT he had been given on the teams previously played for.
But IMO, he has already proven in just 4 games to have the size / speed / vision / intelligence / competitiveness / drive / teachability / and team attitude that should make most NFL scouts / coaches take notice. His skill-set certainly seems at least on par with other great BYU RB's that have been drafted (Jamaal Williams, Harvey Unga, Luke Staley, etc). Hope the best for him, and certainly for selfish reasons would love to see him in BYU blue again next year, as we could certainly use him in the gauntlet of games we have to navigate - almost no gimme's next year, and so a solid run game is vital to complement ZW and the passing game.