The injury robs the Lions of their two-headed monster, Jahmyr Gibbs and Montgomery, affectionately known as Sonic and Knuckles. While Gibbs played the big speedster role, Montgomery was the constant workhorse, keeping the Lions on good ground and at distance, making bulldozing tackles and converting short-yardage and goal-line situations. His absence deprives the backfield of a potent weapon.

Without Montgomery, the Lions will likely put a heavier workload on Gibbs. Craig Reynolds could play the short yardage role and rookie Sione Vaki could get some reps.

In October, the Lions agreed to a two-year extension with Montgomery to ensure the pairing with Gibbs continued. Now they may not see the field together again until the 2025 season.

It’s a brutal injury for a Lions club that has been decimated in recent weeks, particularly in defense. Rapoport reported Monday that defensive lineman Alim McNeill suffered a season-ending ACL tear and cornerback Carlton Davis is out six weeks with a broken jaw.

Before Sunday’s injuries, the Lions had 18 players on injured reserve, including 13 defensemen. Aidan Hutchinson, Marcus Davenport, Alex Anzalone, Derrick Barnes, John Cominsky and Kalif Raymond top Detroit’s key injured list.

Detroit is 12-2 and has already secured a spot in the postseason, but mounting injuries have brought some gloom to a team with Super Bowl aspirations.