Michigan QB Wilton Speight will be out for several weeks, Wolverines coach Jim Harbaugh said Monday.

“He wont’ be able to compete this week or for multiple weeks,” Harbaugh said about Speight.

Harbaugh didn’t go into the specifics of the injury.

John O’Korn will be the start as Michigan (4-0) plays rival Michigan State at 7:30 p.m. ET on ABC this Saturday. Michigan then plays at Indiana on October 14 and at Penn State on October 21.

“John’s done a fantastic job every since he’s got here, in every role he’s been in, he’s acquitted himself well, including coming off the bench and leading our team to a victory against Purdue. I think that speaks volumes,” Harbaugh said.

Brandon Peters will be the backup and Dylan McCaffrey is QB No. 3.