The running back position is the least of Utah's worries heading into the 2015 season. Utah's identity on offense last season was clearly it's run game, namely Devontae Booker. With no drastic improvements at the quarterback or receiver positions and with Booker's return as the top back in the Pac-12, Utah will rely heavily on the running game to spur offensive production and open up the passing lanes for the quarterbacks.
The running game for Utah in 2015 will essentially be a one man show, with Booker getting as many carries as he wants. As menitoned earlier, Booker is the bell cow for this Utah offense.