It's 2nd and 1 after Michigan's defense forced a punt following the Gardner interception. Michigan comes out in a traditional pro-set I-formation. Minnesota has stacked the box with nine players. Michigan will run the ball anyway, but that's not the real problem. Michigan will run a power running play (including a pulling lineman; Patrick Omameh) to the strongside of the field (bottom of the screen). Mealer has a defensive tackle lined up directly over him who he should block he up, especially because Omameh--to his right--is pulling across the formation. But...
...as the ball is snapped, Mealer totally ignores the defensive tackle (highlighted). Omameh has started to pull across the formation essentially leaving a wide-open hole for the DT to run through.
The defensive tackle is now running into Omameh, who isn't expecting contact (highlighted). Notice also that Taylor Lewan is also blocking the player that Mealer reached for, so Lewan, Mealer, and Ricky Barnum are all blocking one player.
By the time Gardner hands the ball off to Fitz Toussaint, Omameh has been pushed four yards behind the line of scrimmage by the unblocked defensive tackle....
... who runs over Toussaint in the backfield for a four-yard loss.
Elliott Mealer is not working out. Mealer has struggled all season, but it hasn't been quite as apparent until this game. I don't know how much of this performance falls on the shoulders of the coaching staff (Mealer looks totally unaware of his responsibilities) and how much is Mealer just failing to get the job done. I'm inclined to think the latter because of how well the coaching staff has done with everyone else. I had high hopes for Mealer this season as someone who was recruited by Carr and finally getting the chance to work in a system like that again, but he's clearly in over his head. Getting beaten by a defender is one thing, but Mealer doesn't even appear to know who he's supposed to be blocking. I don't know if Michigan has any other options at center this year without burning a redshirt, but it may be time to start considering all options (at least if Michigan is back in contention for the Big Ten title).