Michigan's run game has been less than stellar this season outside of Denard Robinson, who has carried the majority of the rushing load. In fact, Michigan's second-leading rusher is Fitzgerald Toussaint, who has only 92 rushing yards in his two games.
Coach Brady Hoke has said that the offensive line play has been a part of Michigan's struggles, but Robinson seems to be immune from that, averaging 8.8 yards per carry.
Outside of Toussaint, none of Michigan's other options at running back has proven he is a reliable back who can step in and replace Robinson's production once he graduates. That unknown is something that might help Michigan in its pursuit to bolster the RB position.