If they don't succeed there then he helps them play where he needs them most or where he thinks they will have more success.
I think his RB skills are better suited for BYU's offense than Utah's. He isn't really the type of back that is dangerous with the ball in space where Utah likes their RBs to be. He is more of an N-S runner that can carry LBs on his back.
LB is probably a clearer path for him to the NFL than RB especially at BYU.