Joe Rexrode

Gannett Michigan

It was already going to be difficult for Indiana to upset Michigan State, but now it’s going to take an improbable performance from an unproven quarterback — to go with a career day from running back and Heisman darkhorse Tevin Coleman.

Indiana coach Kevin Wilson made official Monday what was feared Saturday when starting quarterback Nate Sudfeld went down in a 45-29 loss at Iowa: Sudfeld has a separated left (non-throwing) shoulder and is out for the season. That has big implications for Saturday’s game between No. 8/6 MSU (5-1, 2-0 Big Ten) and Indiana (3-3, 0-2) at Memorial Stadium (3:30 p.m., ESPN).

True freshman and converted linebacker Chris Covington replaced Sudfeld at Iowa and had a rough go of it — 3 for 12 for 31 yards and two interceptions. The Hoosiers may have had a chance at the upset with Sudfeld, considering Coleman had touchdown runs of 83, 69 and 45 yards, finishing with 219 on 15 carries.

Wilson said IU may take the redshirt off freshman Zander Diamont. He’ll compete this week with Covington and walk-on sophomore Nate Boudreau. Either way, MSU’s defense will be getting after a young, inexperienced quarterback.

IU’s high-tempo offense has given MSU some trouble in the past two seasons, scoring 27 in 2012 and 28 last season. Sudfeld and Tre Roberson split time in MSU’s 42-28 home win last season, but Roberson transferred to Illinois State in the offseason.

Coleman opened last season’s game with a 64-yard touchdown run, then finished with 15 carries for 79 yards. The junior leads the nation in rushing yards (1,060) and averages 8.83 yards a carry. According to the Indianapolis Star, that puts him on pace to beat Mike Rozier’s major-college record of 7.81 per carry, set in 1983 (minimum 215 carries).

The question is what the quarterback situation might do to IU’s running game. Wilson said quarterback runs likely will become a bigger part of the offense.

Joe Rexrode is a reporter for the Detroit Free Press.