The hits keep coming for the Detroit Lions.

Running back David Montgomery will undergo season-ending knee surgery, head coach Dan Campbell told reporters on Monday. According to multiple reports, Montgomery was diagnosed with a torn MCL.

Montgomery was evaluated by coaches in the second quarter of Sunday’s 48-42 loss to the Buffalo Bills. After testing his knee on the sideline, Montgomery decided to get back into the game. He finished the game with five carries for four yards.

“David is so tough, man. He continued to play through it and then had it checked today,” Campbell told reporters on Monday. “He’s just the ultimate teammate, the ultimate competitor. We will miss him.”

Montgomery also suffered a knee injury earlier this season in the first quarter of the Lions’ Week 6 win over the Minnesota Vikings. Although he was initially listed as questionable after being helped off the field, Montgomery returned to the game in the second quarter. It is unclear whether the injury affects the same knee or whether the injuries are related.

This year it’s been a bloodbath for the 12-2 Lions, who are playing exceptionally well but have been devastated by injuries.

Most of Detroit’s losses came to defensive players, including defensive lineman Aidan Hutchinson’s season-ending leg injury. In Sunday’s loss, the Lions lost two cornerbacks in one half, with Carlton Davis III suffering a season-ending jaw injury and Khalil Dorsey being carted off the field with a brutal-looking ankle injury. Defensive tackle Alim McNeill also suffered a season-ending ACL tear on Sunday.

Now the team will have to play without Montgomery, who accounted for a large portion of the offensive production this season. The running back started all 14 games and recorded 775 yards and 12 touchdowns on 185 carries.