Sep 21, 2025; Santa Clara, California, USA; San Francisco 49ers head coach Kyle Shanahan on the sidelines against the Arizona Cardinals during the second half at Levi's Stadium. Mandatory Credit: Cary Edmondson-Imagn Images Cary Edmondson-Imagn Images

How Big NFC West Injury Impacts the Rams

Originally posted on Los Angeles Rams on SI
By Brock Vierra | Last updated Sep 22, 2025 5:20 PM ET

News coming out of San Francisco is that 49ers star defender Nick Bosa is believed to have suffered a torn ACL in the 49ers' win over the Arizona Cardinals on Sunday. In the 49ers' home victory, Bosa was forced to leave the game early, and tests confirmed the results on Monday.

"Tests today showed that 49ers Pro Bowl DE Nick Bosa suffered a season-ending torn ACL during Sunday’s win over Arizona, sources tell ESPN," stated ESPN NFL Insider Adam Schefter. "It’s a clean tear, but Bosa now will need season-ending surgery."

Kyle Shanahan

Joe Nicholson-Imagn Images

"There is concern because of how he feels," stated Shanahan on Sunday. "They do the test and stuff on the sideline and usually they say whether he definitely did or not [injure his knee], and they didn't say that. But we are concerned with that. Keeping our fingers crossed for the MRI."

Trent Williams

"Anytime you lose a guy like Nick and his status is unknown, it's a real buzzkill," Williams said after Sunday's contest. "It is cliché to say the next man up, but when you lose a guy like that, you need three or four guys to come to fill those shoes. I think we've got the depth and we got the youth, so hopefully they can continue to improve."

How Does This Affect the Rams

The Rams are set to take on the 49ers on Thursday Night action in ten days (week five) at SoFi Stadium, and if results hold, it's expected that the contest will determine first place in the NFC West.

The Rams and 49ers are already entangled in one of the most fierce rivalries in the NFL, a rivalry that has taken on a new life with both sides adding new blood, blood that has assimilated into the cultures that fuel both teams.

D. Ross Cameron-Imagn Images

With Bosa off the field, the 49ers' defensive strategy must take a new form. For defensive coordinator Robert Saleh and in the Shanahan era, the team's approach to defense is to pay a star at every level and then scheme up other defenders with certain skills to get the best out of all players.

In 2025, the money resides with Bosa, Fred Warner, and Deommodore Lenoir. The 49ers also added a bunch of talent in the draft, including Mykel Williams, their first-round EDGE from Georgia.

However, this automatically gives the Rams a massive advantage on the line of scrimmage.

This article first appeared on Los Angeles Rams on SI and was syndicated with permission.

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