STATE COLLEGE, Pa. (AP) — The Big Ten Conference banned Jim Harbaugh from coaching at Michigan’s three remaining regular-season games on Friday, defying a warning from the second-ranked Wolverines in an extraordinary confrontation over an alleged sign-stealing scheme that has rocked college football.

Harbaugh was disciplined by the conference less than 24 hours before the Wolverines play at No. 9 Penn State in their toughest matchup of the season so far. His team (9-0) has a shot to win a third straight Big Ten title and the school’s first national championship since 1997.

There was no immediate response from Michigan, whose planed landed in Pennsylvania shortly before the announcement.

Michigan was prepared to take possible legal action if the conference punished the football program before a full investigation into the allegations. The NCAA and the Big Ten are both looking into the claims. Getting a court order could prove difficult before Saturday’s game; Friday is the recognized federal holiday for Veteran’s Day and courts were closed.

The Big Ten said the school had violated its sportsmanship policy by conducting “an impermissible, in-person scouting operation over multiple years” that resulted in “an unfair competitive advantage that compromised the integrity of competition.” As a result, the Big Ten said Michigan must play without Harbaugh against the Nittany Lions (8-1) this weekend, next week at Maryland and in the annual showdown game against rival and No. 3 Ohio State two weeks from now. While Harbaugh is allowed at practices and other activities, he cannot be “present at the game venue.”