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Carolina Panthers owner David Tepper did indeed have a phone conversation recently with Michigan head coach Jim Harbaugh. But the Panthers owner didn't initiate the call.

Sources tell CBS Sports that Harbaugh -- or his representation -- had been calling Tepper with some regularity in recent weeks. Tepper eventually held a conversation with Harbaugh, but it was never characterized as a job interview for the permanent head coaching job in Carolina.

Sources around the league have indicated Harbaugh is interested in returning to the NFL, where he excelled as head coach of the San Francisco 49ers from 2011 through the 2014 season. News broke Thursday night that Michigan is facing NCAA rules violations, including a Level I violation against Harbaugh.

"I am aware of the rumors and speculation over the past few days," Harbaugh said in a statement Thursday before news broke of possible NCAA infractions. "College and NFL teams have great interest in all our personnel, from players to coaches to staff, and I truly believe that is a testament to the strength of our University of Michigan football program.

"As I stated in December, while no one knows what the future holds, I expect that I will be enthusiastically coaching Michigan in 2023."

Reports out of Minnesota about Harbaugh's interview last year with the Vikings made Tepper wary, sources say. A lengthy interview between the Vikings and Harbaugh last January didn't result in an offer, and sources describe Harbaugh's behavior during the interview as "odd."

Carolina fired head coach Matt Rhule five weeks into the regular season. Interim head coach Steve Wilks got the Panthers on the precipice of the NFC South title, but last week's loss to Tampa Bay ended those hopes. Wilks, known for his leadership qualities and with the backing of many Panthers players, will be considered for the permanent job.

After firing Rhule this season, Tepper was believed to eventually eye an offensive-minded coach already in the NFL. Lions offensive coordinator Ben Johnson, Cowboys offensive coordinator Kellen Moore, Bills offensive coordinator Ken Dorsey could be among the coaches that Carolina requests to interview.