The San Francisco 49ers’ injury woes worsened on Sunday, with star defensive end Nick Bosa leaving the Week 3 NFC West clash against the Arizona Cardinals due to injury.
Despite a hard-fought 16-15 victory and a 3-0 start to the season, Bosa’s absence could have major implications for the 49ers’ defense moving forward. Here is the latest update on the 49ers DE injury.
What Happened to San Francisco 49ers’ Nick Bosa?
Bosa exited the field towards the end of the first quarter as the Cardinals were set to punt back to the 49ers. Once he got to the 49ers’ sideline, he fell to the ground and was in clear pain.
The Pro Bowler appeared to have suffered a knee injury, and as he left the field, he gave fans a thumbs down, signaling concern about his condition.
If Nick Bosa is seriously injured, how do the #49ers replace him?
As Trent Williams explains, it’s not really that simple. #FTTB | @kpixtv pic.twitter.com/cTl0cz8B9b
— Matt Lively (@mattblively) September 22, 2025
Head coach Kyle Shanahan addressed the situation postgame, noting that initial tests did not indicate an ACL injury but expressing concern about the way Bosa left the game.
“There is concern because of how he feels,” Shanahan said. “Hopefully we’ll have some good news tomorrow.”
Nick Bosa’s Latest ACL Injury Update
The 49ers’ injury nightmare has taken a new turn: Bosa is believed to have suffered a torn ACL during Sunday’s 16-15 NFC West win over the Cardinals, potentially ending his season, according to ESPN NFL Insider Adam Schefter.
“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,” Schedter posted on X. “It’s a clean tear, but Bosa now will need season-ending surgery.”
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. It’s a clean tear, but Bosa now will need season-ending surgery. pic.twitter.com/f6xdHY0iVS
— Adam Schefter (@AdamSchefter) September 22, 2025
Bosa started the season on fire, ranking second in tackles on the 49ers defense through the first two weeks and entering Sunday with the team lead in sacks. He paired those two sacks with four tackles for loss, continuing to dominate at the line of scrimmage. His presence has been a cornerstone of San Francisco’s defensive success.
For 49ers fans, the worst fears have been confirmed. San Francisco’s defense has already been battered during the first three weeks of the season, and losing Bosa is a major blow.
San Francisco will now prepare to face the Jacksonville Jaguars on Sunday, Sep. 28 at Levi’s Stadium, hoping to adjust without one of their defensive anchors while eyeing for a 4-0 start to the campaign.
