49ers star DE Nick Bosa (knee) to undergo testing

Field Level Media|published: Sun 21st September, 20:21 2025

NFL: Arizona Cardinals at San Francisco 49ers

Sep 21, 2025; Santa Clara, California, USA; San Francisco 49ers defensive end Nick Bosa (97) on the field during warm ups prior to a game against the Arizona Cardinals during the first half at Levi's Stadium. Mandatory Credit: Cary Edmondson-Imagn Images

San Francisco 49ers standout defensive end Nick Bosa injured a knee during Sunday's victory over the Arizona Cardinals and will undergo further evaluation.

San Francisco coach Kyle Shanahan said the seriousness of the injury isn't yet known.

"No, we can't rule anything out," Shanahan said after the 16-15 victory. "They checked for ACL and stuff there. He was good with that, but we're still not sure, so we gotta check with more things tonight and tomorrow."

Bosa was injured in the first quarter while being double-teamed during an Arizona pass play. His knee bent awkwardly as he fell to the ground and he left the contest and didn't return.

Bosa had two tackles and a forced fumble before departing.

Bosa, a five-time Pro Bowl selection, is in his seventh season with San Francisco. He was the NFL Defensive Player of the Year in 2022 when he recorded a career-high 18.5 sacks.

--Field Level Media