University of Michigan head coach Jim Harbaugh has made a change on his staff.

A source told Sporting News that Kevin Tolbert, who had served as the team’s strength and conditioning coach the past three seasons, won’t be returning to the Wolverines’ football program in 2018.

A replacement was not immediately known.

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Tolbert had worked under Harbaugh the past nine seasons starting at Stanford University (2009 and 2010) and then the San Francisco 49ers (2011 to 2014). Tolbert followed Harbaugh to Michigan when the latter was named head coach in 2015.

Tolbert had served as the Wolverines’ assistant strength and conditioning coach from 2001 to 2007 before accepting the same position with the Detroit Lions in 2008.

Michigan (8-4) plays its final game of the season January 1 against South Carolina (8-4) in the Outback Bowl in Tampa.

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