One report claims Wilton Speight broke his left collarbone and is done for the season.

Another states the Michigan sophomore quarterback is week-to-week.

As for coach Jim Harbaugh, he says his star signal caller is questionable when the No. 4 Wolverines host Indiana in Big Ten play on Saturday (3:30 p.m. ET, ESPN).

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Speight suffered the injury during the fourth quarter of last Saturday's 14-13 loss to Iowa. News of the injury began circulating on Monday, but Harbaugh declined to confirm the seriousness of the injury or discuss any other details related to Speight.

Harbaugh was a little more forthcoming Tuesday during a Big Ten teleconference, but he still refused to confirm whether the collarbone is broken.

"I never really get into that talk; I'm not a doctor," Harbaugh said. "I'd hate to be the third person talking about these things. He remains questionable for Saturday and we'll reevaluate after that."

Speight isn't practicing this week and all indications point to junior John O'Korn drawing the start against the Hoosiers (5-5, 3-4).

O'Korn has previous starting experience at Houston and waged a tight battle for Michigan's starting job before being beaten out by Speight during fall camp.

O'Korn passed for 3,117 yards and 28 touchdowns against 10 interceptions as a freshman in 2013. He lost the starting gig at Houston the following season when he passed for 951 yards and six touchdowns against eight interceptions.

He sat out last season as a transfer and has served in the mop-up role this season. O'Korn has completed 13 of 18 passes for 114 yards and two touchdowns, but the offensive players have seen enough of him in practice sessions to feel he will be more than a capable fill-in.

"If John's number is called, we're fully confident in him; we've seen what he can do since he got here," senior tight end Jake Butt said. "He's been a hard worker, a great note taker, a great leader and he's got everything you need to get the job done."

O'Korn also will be stepping into a must-win situation. The Wolverines (9-1, 6-1) have no margin for error after the loss to Iowa.

After the Indiana contest, Michigan will face what is basically an elimination game in terms of the national championship picture when it plays Ohio State.

"All we can do is control the future, and so that's the only thing we're focused on," senior safety Dymonte Thomas told reporters. "It allows us to see how strong we really are. This allows us to see how we're going to bounce back and respond.

"Every team is going to face adversity throughout the season. So, the best teams are the ones who can overcome adversity."

Indiana certainly doesn't have the greatest timing to have to visit Ann Arbor one week after Michigan's pivotal loss.

Making matters worse: The Hoosiers have lost 20 straight games against the Wolverines. In fact, Indiana has won just once (in 1987) in the past 36 meetings.

"We've got a great challenge, great opportunity," Indiana coach Kevin Wilson said. "I know the kids are looking forward to it. It will be a big week as we move into this one."

The Hoosiers had a chance at an upset last Saturday against No. 10 Penn State but let a 10-point, third-quarter lead get away and allowed 31 points in the final 16-plus minutes to fall 45-31.

Junior running back Devine Redding rushed for 108 yards and two touchdowns while notching his fifth 100-yard outing of the season. Redding has 901 yards and five scores.

Junior quarterback Richard Lagow has been turnover-prone, with 13 interceptions, while passing for 2,866 yards and 17 touchdowns.

Defensively, the Hoosiers allow 28.4 points per game. Junior middle linebacker Tegray Scales has a team-leading 94 tackles and is tied with sophomore defensive end Nile Sykes for the team lead with four sacks.

The Wolverines continue to lead the nation in scoring defense (11 points per game), total defense (244.7 yards per game) and passing defense (131.6). Michigan is also sturdy against the run, ranking 13th nationally (113.1).

Sophomore outside linebacker Jabrill Peppers has spurred the season-long domination and has a team-best 14 tackles for loss. Cornerback Channing Stribling has a team-leading four interceptions.

Michigan will be looking to bounce back from the Iowa loss, but the Hoosiers feel they are in a similar predicament after missing out on the upset against Penn State.

"We get another shot to go up north and play another, great Top 10 team," senior guard Jacob Bailey said. "We have a chance to redeem ourselves. We have a second chance, and those do not come around often in life."