Buffalo Bills defensive end Von Miller underwent surgery Tuesday, head coach Sean McDermott told reporters Wednesday.
The surgery was exploratory and resulted in an unexpected ACL repair. He will be out for the season, the Bills announced.
Miller suffered the knee injury in Week 12 against the Detroit Lions. A Detroit offensive lineman hit his leg from the side on a pass play in the first half, and his leg was rolled up on as the play ended. He was carted off the field and soon ruled out for the game.
An ACL tear was initially ruled out and the 33-year-old said on his podcast that he hoped to return by Week 14. The Bills placed him on injured reserve just a week before announcing Miller won't come back at all.
This is not Miller's first ACL tear, as he suffered the same injury 2013 on the same knee. Two seasons later, Miller was the Super Bowl 50 MVP for the Denver Broncos.
He went on to help the Los Angeles Rams in their Super Bowl-winning campaign after a midseason trade last season. The Bills had their own Super Bowl goals this year and signed him to a six-year, $120 million deal in the offseason.
"Unfortunate situation, for Von, obviously, and our team. Care for him, obviously, like we would any player," McDermott said. "We know how much this means to him in terms of playing and being with the team, so we look forward to getting him back, obviously off the field for the rest of the season and his leadership, and we're certainly thinking about him as he recovers here."
Miller recorded a team-leading eight sacks in the Bills' first eight games and will finish the year with 21 combined tackles, 12 quarterback hits, two passes defensed and one forced fumble in 11 games.
He had a message to fans from his hospital bed: "I'm excited for the opportunity to show my teammates how tough I am, how hard I work and how important that this means to me," he said in a video posted on Twitter. "Don't blink! I'll be back."