I'm calling Bullschit. Mullen is known for favoring upperclassman. Wright has been given a shot. Why isn't Lorenzo? I guess he sucks.
Most every coach favors upperclassmen, that's not really something exclusive to Mullen. And it's understandable why: they've put in the time and effort into the University and usually know the nuances of the game far better.
That said, I don't think Mullen can be criticized on this one: we have one of the best offenses in the country and our RBs have played an important role in that. It'd be a different case if the guys who were playing weren't producing while a talented guy like Lingard sits on the bench; but as a group, they're averaging something like 4 yards a carry and 7-9 yards per catch (could be higher after this last weekend's Cocktail Party). That's excellent production, no matter how you slice it. At the end of the day, if Lingard can't beat out the guys in front of him, that's on him, not the coach.