ANN ARBOR -- The Michigan football team will be without Ben Mason for the remainder of spring.

Mason, who will be a sophomore this season, plans to have surgery to repair a torn meniscus he suffered in practice, head coach Jim Harbaugh revealed this week on his "Attack Each Day" podcast.

"He was cracking skulls, doing Ben Mason stuff," Harbaugh said. "As spring ball was going, he complained a little bit about his knee. His knee just didn't feel right."

Harbaugh said the Michigan training staff couldn't find anything wrong with him originally, but an MRI later revealed the tear. It's unclear which knee Mason injured -- but the surgery is going to leave him sidelined for approximately six weeks.

"It'd be better to go in and have surgery on the (meniscus) tear than to keep playing on it," Harbaugh said. "So, he's going to get a meniscus surgery."

Mason, listed at 6-foot-3 and 253 pounds, was in the process of transitioning back to linebacker. The plan was for him to play there and at fullback in 2018, an effort to capitalize on his hard-hitting style.

He played in all 13 games as a true freshman in 2017, on special teams and at fullabck, where he had three carries for four yards and two touchdowns. The Newton, Conn., native was voted Michigan's "toughest player" by his teammates.

"We'll get him back fully up to speed," Harbaugh said. "I love the medicine these days. They treat the meniscus and sew it back together, rather than cutting the meniscus out and 20 years later you don't have any meniscus left.

"But yeah, he would have kept going if he didn't have that MRI."

Mason joins tight end Tyrone Wheatley, Jr. (broken foot) as the second known Michigan football player to suffer a second practice-ending injury this spring.