The San Francisco 49ers confirmed Monday that defensive star Nick Bosa has torn the ACL in his right knee and will require surgery. The Pro Bowler had left Sunday’s 16-15 win over the Arizona Cardinals with a right knee injury, and did not return. Initial tests done by the team’s training staff came back negative, but after an MRI on Monday, it was determined Bosa tore his ACL and will miss the rest of the 2025 NFL season.

Sources told ESPN’s Adam Schefter: “Tests today showed that 49ers Pro Bowl DE Nick Bosa suffered a season-ending torn ACL during Sunday’s win over Arizona. It’s a clean tear, but Bosa now will need season-ending surgery.”

Bosa’s injury occurred while he was pressuring quarterback Kyler Murray from the left edge. After initial contact with left tackle Kelvin Beachum, Bosa was hit by guard Evan Brown in a double-team and fell on the field.  Head coach Kyle Shanahan had told reporters on Sunday that it wasn’t a confirmed tear, but the team feared the worst: “There is concern because of how he feels. Usually, the tests are conclusive one way or another, and this time they weren’t. We were still worried and waiting on the MRI.”

Bosa had been off to a strong start with two sacks, 15 tackles, eight quarterback pressures, and a 21.9% pass-rush win rate. The latest injury for Bosa marks the second time in his career that he has suffered a season-ending ACL injury. He previously tore the ligament in his left knee during a Week 2 game against the New York Jets in 2020. Back in 2015, as a high school senior, he also sustained a partial ACL tear in the same right knee.

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