Who do you think will be the workhorse in the Broncos' backfield this year?

Specifically, who will have the most fantasy relevance? Their backfield is packed: Moreno, Torain, Arrington, Young, Jordan, Hillis, Buckhalter. Moreno is probably the favorite to start, but a lot of these guys have experience already. Shanahan was really high on Torain last season, but he never got a chance to really get going with his injuries. Any thoughts?