Collin Mooney has been fun to watch when he is on the field. Whether the former Army star is showing out as a run blocker or playing on special teams, he has a certain physicality and technique that other players don't have.
In 2013 Mooney was a fullback whose only job was to open up holes for CJ and Shonn Greene. Unfortunately for him, Whisenhunt's offense likely won't need a pure fullback on the roster. Whisenhunt has said (not in so many words) that he believes that someone from the TE or RB group will be able to split time there without wasting a roster spot (which will probably go to one of the 9,000 DTs on the roster).
Jackie Battle has been mentioned as a running back that will see some time at fullback, but it appears Mooney will have to do just the opposite. Now listed as a RB on the roster, he will have to prove that he can do something that the other running backs can't.
Personally I remember Mooney running against the Jacksonville Jaguars and showing some promise. Now he obviously was facing a bad team, but he had solid leg drive and seemed like a guy that could move the pile on 3rd and 2.
If it comes down to it, I would rather have Mooney on the roster than Jackie Battle, and he is by far the cheapest option of all the running backs. I think in the end his versatility on special teams and his ability to be such a good run blocker will lead to him getting one of the final five spots.