Detroit Lions running back David Montgomery According to ESPN’s Adam Schefter, he is out indefinitely after suffering an MCL injury in Sunday’s loss to the Buffalo Bills

“More: Lions RB David Montgomery is now out indefinitely after suffering an MCL injury in Sunday’s loss to the Bills, sources tell ESPN,” Schefter wrote on Twitter. “Montgomery is currently undergoing additional tests on his knee and seeking a second opinion to confirm, but he could be out for the season.”

Montgomery finished the 48-42 loss to the Bills with just five carries for four yards. Despite the shootout loss, the Lions never got into the run game.

NFL insider Ian Rapoport confirmed that Montgomery suffered a torn ACL and could miss the season, which would include the playoffs. The Lions are currently 12-2 and the No. 1 seed in the NFC, tied with the Philadelphia Eagles.

“We never got our running game going, which should be a focus, and even out of those 15 runs we just could never get it going,” head coach Dan Campbell said. “So that’s two weeks in a row. It’s not good enough. And it’s not them, it’s us, and that’s also the frustrating part.”

quarterback Jared Goff threw the ball 59 times in a difficult running game with those involved and without Montgomery.

“I think we had to deviate from the flow of the game in some ways,” Goff said. “Maybe we’ll stick with it if the game is in a slightly different place, it starts to pop and then it’s a different story. I don’t know. But no, there’s nothing significant there.”