The Big Ten formally notified Michigan that it could be facing disciplinary action from the league, a Michigan official told ESPN.

The letter sent to Michigan is part of the Big Ten's sportsmanship policy, which requires a notice of disciplinary action "in the event it becomes clear that an institution is likely to be subjected to disciplinary action." The NCAA is investigating Michigan for illegal off-campus scouting and signal stealing, but Big Ten commissioner Tony Petitti has the authority to impose discipline under the sportsmanship policy before the lengthy NCAA investigative and infractions process concludes.

The Big Ten's letter alludes to evidence of the illegal signal stealing, which compromised competitive integrity and other principles of the sportsmanship policy, according to sources.

Michigan has until Wednesday to respond to the Big Ten, according to sources. Athletic director Warde Manuel on Monday said he will not travel to Texas for College Football Playoff selection committee meetings, and will remain on campus "attending to important matters regarding the ongoing investigation into our football program."

Petitti on Friday met with Michigan president Santa Ono in Ann Arbor, Michigan, where he reviewed some of the information obtained from the NCAA about Michigan's alleged signal-stealing operation. Connor Stalions, a Michigan analyst believed to be at the center of the NCAA's investigation, resigned from his position Friday after initially being suspended with pay.

Potential Big Ten discipline for Michigan likely would be a suspension for coach Jim Harbaugh rather than any team-related punishment, according to sources. The league's sportsmanship policy allows Petitti to impose up to a two-game suspension and a $10,000 fine as standard discipline. Any discipline exceeding those marks would fall under major disciplinary action, and would require approval from the joint group executive committee, which includes officials from several Big Ten schools.

If the Big Ten imposes discipline, Michigan and Harbaugh are expected to explore all legal options to push back against the league, according to sources. Although the sportsmanship policy grants Petitti the authority to "determine whether offensive actions have occurred," the Big Ten's handbook also cites "NCAA initiated cases" and notes that in those cases, its compliance and reinstatement committee "may impose additional penalties, if warranted, subsequent to the NCAA action."

"We're going to explore every single option to make sure Michigan is treated fairly," a source told ESPN.

Ono emailed Petitti in advance of their Friday meeting, urging him to respect due process and the ongoing NCAA investigation.

"It's precisely at these times -- when all key facts are not known but others are all too comfortable offering strongly held opinions -- that it is essential for everyone to ensure that investigations are conducted fairly and that conclusions are based on what actually happened," Ono, who shared his email with the other Big Ten presidents and chancellors, wrote to Petiti. "The reputation and livelihoods of coaches, students, and programs cannot be sacrificed in a rush to judgment, no matter how many and how loudly people protest otherwise. Due process matters.

"We, as would any other member of the Big10, deserve nothing less. Our students, our coaches, our program -- all are entitled to a fair, deliberate, thoughtful process."