Michigan QB Jack Tuttle medica...

Michigan quarterback Jack Tuttle is calling it a career.

Tuttle announced on social media on Monday night that he is retiring from the sport in the middle of the season due to medical reasons. The announcement came amid a concussion, which apparently kept Tuttle out of the Wolverines' 24-17 win over Michigan State on Saturday.

It’s unclear when he sustained that injury, but Tuttle said it was the fifth of his career.

“Unfortunately, the recent experience of enduring my fifth concussion had brought forth the painful truth: That I need to start prioritizing my health,” Tuttle wrote, in part. “Throughout my college career, I’ve battled numerous injuries culminating in this difficult choice to step away from playing the game that I love.”

Tuttle returned to Michigan for a seventh season of eligibility this fall. He got his start at Indiana, and transferred in to back up J.J. McCarthy last season during their national championship run.

He was expected to be the favorite to start this season for the Wolverines, but he went down with an injured right elbow late last year and wasn’t fully recovered by the start of this fall.

Tuttle made his first start against Illinois on Oct. 19, though he went just 20-of-32 and threw an interception in that 21-7 loss. He stepped in to replace Alex Orji in their loss to Washington the week before, too, after Orji struggled early in that contest.

Tuttle, however, did not play against the Spartans on Saturday. Instead, Davis Warren got the start and led them to the win. Tuttle was ruled out for that game ahead of time, but no reason was given. Warren was Michigan's third starting quarterback this season.

In total, Tuttle threw seven touchdowns, eight interceptions and completed just shy of 60% of his passes in 23 games over six seasons in his career.

“Though closing this chapter is unfortunate, my passion for football will always be a part of me,” he wrote. “I am committed to finding a different role in the game and plan to pursue a role in coaching.”

Michigan will host No. 1 Oregon next on Saturday (3:30 p.m. ET, CBS). The Wolverines currently hold a 5-3 record, though they have to take on both No. 13 Indiana and No. 4 Ohio State on the road during their final four games of the season.