While the Detroit Lions’ defense has been ravaged by injury all season, Detroit’s offense has remained relatively unscathed until now.

Head coach Dan Campbell confirmed Monday that running back David Montgomery suffered a knee injury in Detroit’s loss to Buffalo Sunday that will require surgery and end his season.

“He’s just the ultimate teammate,” Campbell said of Montgomery, who finished the game Sunday despite the injury. “Ultimate competitor. We’re going to miss him. He’s another one of these guys at his position helped us to get where we’re at. The rest of us owe him.”

Montgomery’s injury means Detroit will have to navigate the foreseeable future with only one half of the NFL’s best running back duo. Montgomery has 775 rushing yards on the season with a 4.2-yard average per carry and 12 touchdowns, which are tied with Green Bay’s Josh Jacobs and Los Angeles Rams running back Kyren Williams for the fourth most in the NFL this season. He’s also chipped in 36 receptions for another 341 yards.

The Lions will now lean more on Jahmyr Gibbs to carry the load for the league’s No. 4 ranked rushing attack heading into last weekend. Gibbs is certainly capable, already having over 1,000 rushing yards on the season (1,047) with 11 touchdowns. His 5.6-yard average per carry ranks fourth in the NFL behind only Lamar Jackson (6.4), Saquon Barkley (5.9) and Derrick Henry (5.8). He’s also caught 39 passes for 395 yards and three more touchdowns.

“We have a lot of confidence in Gibbs,” Campbell said. “He’s continued to get better and better as the season has gone. Given the opportunity, he’s made a lot of plays. He made some big plays for us (Sunday). He brings an explosive element. He’s getting better in the pass game, and you see what he’s able to do in the run game. We have a ton of confidence (in him).”