Raheem Mostert suffered a knee injury and was ruled out. Cary Edmondson-USA TODAY Sports

49ers RB Raheem Mostert exits against Lions with knee injury

By Erin Walsh | Last updated 9/12/21

San Francisco 49ers running back Raheem Mostert exited Sunday's game against the Detroit Lions with a knee injury and was ruled out for the remainder of the contest.

49ers’ RB Raheem Mostert now ruled out for remainder of today’s game with a knee injury.
— Adam Schefter (@AdamSchefter) September 12, 2021

Mostert had two carries for 20 yards on the Niners' second possession of the game, but he went to the sideline after a nine-yard gain on the second play of the series.

After Mostert's injury, rookie running back Elijah Mitchell filled in and ran for a 38-yard touchdown on the series.

Mostert is coming off an injury-plagued season, playing in eight games last year. A knee sprain and high-ankle sprain sidelined him for half the year.

The 29-year-old's best season came in 2019 when he ran for 772 yards and eight touchdowns in 16 games. He also caught 14 passes for 180 yards and two scores.

If Mostert is sidelined for a significant period of time, Trey Sermon, JaMycal Hasty and Mitchell will see more playing time.

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