Ohio State Buckeyes defensive end Nick Bosa had surgery on Thursday to fix a core muscle injury, and there is no timetable for his return, coach Urban Meyer said.
Bosa, who suffered the injury in the third quarter of a 40-28 victory over TCU on Saturday, will not be on the field for the No. 4 Buckeyes this weekend against Tulane.
Already this season, the junior standout has four sacks, which is tied for third in the nation, a team-high 14 tackles and a forced fumble that resulted in a defensive touchdown.
Bosa, who Meyer called one of the best players in college football earlier this week, was listed as the No. 1 prospect for the 2019 NFL draft on Mel Kiper's Big Board on Thursday.
Defensive tackle Dre'Mont Jones said he wasn't sure how Bosa's absence would change the way opposing offenses try to attack the line of scrimmage.
"It's hard to say; we haven't played anybody without him yet," Jones said. "We'll see on Saturday."
Bosa, the Big Ten defensive lineman of the year in 2017, led the Buckeyes with 8.5 sacks, 16 tackles for loss and nine quarterback hurries last season.
"I'm not going to hold it back: He's our star player. He's our LeBron," Jones told ESPN Radio on Saturday. "... We knew we got a bunch of guys on the D-line that can ball."
Saturday's game will only be the second time in the last 73 games that a Bosa will not be on the field for the Buckeyes. Nick's older brother, Joey, blossomed into the No. 3 overall pick by the Los Angeles Chargers in the 2016 NFL draft after his junior year.