Injuries to Nick Bosa and Fred Warner gutted a star-driven San Francisco 49ers defense in 2025. They’ve been the driving force in what’s been one of the best defenses in the league dating back to 2019. Losing Mykel Williams for the season didn’t help. Neither did fielding multiple rookies and journeymen along the way.
Despite a relatively easy schedule, the 49ers finished in the bottom 11 in EPA per play against both the run and the pass.
In a sit-down with Tom Tolbert, head coach Kyle Shanahan shared
why he believes the 49ers defense wasn’t exposed in 2025 more than they could have been:
I think we need to be better on defense all-around in terms of, we got fortunate last year, we didn’t play a ton of quarterbacks, so I think that helped us not get as exposed, but we went in a little light, just because of losing guys in free agency and stuff.
Shanahan is as blunt as it gets when it comes to quarterbacks faced. There were backups and rookies littered throughout the schedule. Robert Saleh worked miracles to make the opposing offense earn every yard.
Shanahan acknowledged that Saleh did a good job. He also understands they still were not good enough:
I knew we were going in light, but I didn’t know we would lose Nick Bosa and Fred Warner. Doing that made it really tough. I think Robert Saleh did a great job. I think our guys rose to the challenge and did a great job, but we weren’t good enough.
And I think what we’ve done in free agency, what we’ve done in the draft, the guys that did get all this experience last year who are better now, bringing Raheem Morris, I think that will be the challenge, to be that much better. Not just in the run, but everywhere.
The good news for the 49ers is that it would be tough to put a worse product on the field than they did last season. The team was starting linebackers in December who weren’t on the roster in mid-November. The defensive line never stood a chance to be competitive.
That changes this season with the return of Bosa and Mykel to the lineup. Osa Odighizuwa projects to be the best passing-rushing defensive tackle since DeForest Buckner. Warner in the middle is the great equalizer. He takes pressure off the safeties and linebackers in coverage. Add in Dre Greenlaw’s ability as a plus run defender, and a season outside of the top-10 — provided health — would be a disappointment.
