Michigan's top two options at the position, Vincent Smith and Justice Hayes, took two very different paths to Michigan.
Smith is a product of Pahokee High School in Florida, commonly known as the place where they chase rabbits in order to become quicker. Standing at 5'6", 160 he was a generic three-star recruit that Rich Rodriguez eyed to fill one of his many running back/slot ninja positions. He lacks the extra gear needed to outrun defenders but his lateral agility is good to great and he has surprising power and balance for such a small player. He held other offers from Wisconsin and Tennessee.
In his freshman year Smith saw spotty carries throughout eight games, followed by a sophomore season where he would nearly triple his carries and double his yardage playing beside Denard Robinson. In 2011 his numbers dropped toward his freshman marks, but he did have that screen play against Notre Dame:
At 9:08 you can watch him run behind what should be a wall but instead is one glob of lineman who don't know how to block. He still makes the play and will forever be remembered for it.
Justice Hayes attended Grand Blanc High School in Michigan, where he was rated as a four-star running back by Rivals and the 85th player overall. I was actually a bit surprised at just how highly rated he was but Rivals calls his agility "as good as it gets" while his speed and elusiveness are at a "blue chip" level. Remember when Rivals used layman's terms to describe prospect attributes? Me neither.
Hayes would redshirt in 2011 and become more familiar with a college weight room. He came into Michigan at 5'10", 175 and will probably hover around 185 to 190 by the time he fills out. He could become a back that contributes in more than just third-down situations but for now he's a lean back who should do a nice job playing behind Vincent Smith until he has all of the assignments down.
Both of these backs are talented in their own way and Michigan needs to find a way to get them involved. We already know what Smith can do on third down as a receiver and as a blocker so I don't expect him to totally fall off of the map in his senior year despite having more competition for the spot than usual. His carries aren't going to soar this year, in great part to Fitzgerald Toussaint locking down the starting running back position halfway through last year. Expect Smith to remain a steady option as the miniature third-down running back who can be useful as a screen receiver or even as a slot. His statistics shouldn't be too far off from his junior campaign.
Hayes, on the other hand, is somewhat of a mystery back. He has yet to accumulate any statistics so we won't know exactly what he brings to the table until we can see him in pads against a higher level of competition. Reports from spring ball and summer drills have been positive, as they should be when you possess the kind of athleticism that Hayes flashes. Given the opportunity he could step into a role very similar to Smith's, catching the ball out of the backfield or even running beside Denard Robinson. If he shows out well in his first few touches he could supplant Smith given his athleticism.
Overall the position is in good hands. Smith is a proven commodity as a receiver and a back who brings surprising balance along with his agility. Hayes could turn out to be an upgrade due to his athleticism, so it's only a matter of time before he learns to pick up blitzes and contribute on third down, either this year or next.
UPDATE: With Toussaint out indefinitely Smith should end up being the #2 overall back behind only Thomas Rawls, and possibly the #1 overall depending on game plans. Even when Toussaint is inserted back into the lineup it might be as a part-time back so Smith's carries and yardage should match those from last year.
Toussaint's suspension could have an effect on Hayes' playing time but it all still depends on the performance of Smith, so I won't be predicting his statistics. He will still be a role player.