The Arizona Cardinals are facing uncertainty at running back heading into their Week 18 matchup against the San Francisco 49ers. Head coach Jonathan Gannon revealed Wednesday that the team is unsure if James Conner will be available after he aggravated his knee injury during the Week 17 loss.

With Conner’s status up in the air, the Cardinals are already without backup running back Trey Benson, who was placed on injured reserve Tuesday due to an ankle injury. The third-round rookie had missed the last two games and will now miss the remainder of the season.

Benson, who had served as Conner’s primary backup, rushed for 291 yards on 63 carries with one touchdown this year, averaging 4.6 yards per attempt. He also added 59 yards on six receptions. His absence leaves a significant hole in the backfield as the Cardinals prepare for their final regular-season game.

-Sagar