49ers' Raheem Mostert to Undergo Season-Ending Surgery on Knee Injury

San Francisco 49ers running back Raheem Mostert announced Tuesday that he would be undergoing season-ending surgery on his knee after injuring it in the first quarter of the team's Week 1 win over the Detroit Lions.

The Niners had placed Mostert on injured reserve Monday due to the running back suffering torn cartilage in his knee.

The 29-year-old's career has been unfortunately beset by injury. He was placed on injured reserve in both the 2017 and 2018 seasons, cutting them short. After being largely healthy in 2019, knee and high ankle sprains cost him eight games in 2020. 

But when he's been healthy over the past few seasons, he's been excellent. Between the 2019-20 campaigns, he rushed for 1,293 yards and tallied 13 total touchdowns across 24 games. After taking over as San Francisco's lead back in 2019, he posted an absolutely epic performance in the NFC Championship Game win over the Green Bay Packers, rushing for 220 yards and four scores. 

It's fair to wonder what heights a fully healthy Mostert would have hit this season or last. He appeared to be on the verge of stardom. 

Instead, the Niners will turn to a young backfield trio of Elijah Mitchell, JaMycal Hasty and Trey Sermon. Mitchell would appear to be next in line to serve as the team's starter after rushing 19 times for 104 yards and a score in the win over the Lions. 

Coming into the season, it appeared that Sermon was the heir apparent to Mostert. But that was called into question when he was surprisingly inactive during Week 1. For now, the gig would appear to belong to Mitchell. 

As for Mostert, his future is completely up in the air. He'll be a 30-year-old unrestricted free agent this summer with a history of injury concerns. The potentially cruel reality for the veteran running back is that NFL teams have trended toward avoiding those types of players in the modern game.