Until this week, Ohio State’s Urban Meyer was among the most valuable coaches in college football.

He has shepherded Heisman Trophy winners and top draft picks, like Tim Tebow and Alex Smith, and has won relentlessly, guiding his teams at Florida and then Ohio State to three national championships since 2006. In his six seasons in Columbus, Meyer’s Buckeyes have gone 73-8, giving him a higher winning percentage than Nick Saban has in 11 seasons at Alabama.

Then, in a matter of hours Wednesday, he became arguably the most radioactive coach in the game. Ohio State placed Meyer, 54, on paid administrative leave while it investigates whether he knew about domestic violence allegations against a longtime assistant. The move signaled that Meyer’s immaculate on-field performance — and the $7.6 million salary he is slated to receive this year after signing an extension — may not be enough to save his job.

On Thursday, the university’s board of trustees announced that it had formed a special independent board for the investigation, saying that the working group would direct the investigative team. The panel includes the trustees Alex Fischer, Janet Porter and Alex Shumate; Jo Ann Davidson, a former speaker of the Ohio House of Representatives; Craig Morford, a former acting United States deputy attorney general; and Carter Stewart, a former United States attorney for the Southern District of Ohio. Also Thursday, the university announced that ordinary media availabilities with the acting head coach, Ryan Day, and players had been canceled for the time being.

That Meyer’s job hangs in the balance despite superlative coaching and no known risk of N.C.A.A. sanctions is the latest example of an unmistakable shift in big-time college sports.