_This is the sixth installment of our eight-part series “State of the 49ers.” We’ll assess each position group and introduce solutions that could help the team on its Super Bowl hunt — continuing with the defensive line._
The 49ers’ defensive line was simply too injured in 2025 to allow for a straightforward evaluation. And that’s immensely frustrating, because last year’s ouster of several veterans — coupled with the addition of draftees Mykel Williams, Alfred Collins, and CJ West — left our curiosity starving for progress reports.
It’s easy to forget how good the 49ers’ defense was to open the 2025 season, before edge rusher Nick Bosa and linebacker Fred Warner went down in Weeks 3 and 6, respectively. The D-line sealed two road wins. The 49ers held the eventual Super Bowl champion Seattle Seahawks and New Orleans Saints to -.108 expected points added (EPA) per drop back, a number that would’ve ranked No. 1 of all NFL defenses — by a wide margin! — if extrapolated over the whole season.
The 49ers’ overall defensive score over that start would’ve ranked No. 3, barely behind only Seattle and the Houston Texans — and way ahead of the rest of the league.
For more context on that, consider what 49ers coach Kyle Shanahan said during the Super Bowl pregame show — before the Seahawks smothered the New England Patriots.
“I think there were only two Super Bowl defenses this year, and it was Seattle and Houston,” Shanahan said. “They’re capable of winning totally on their own if the other side of the ball doesn’t mess it up.”
Might coordinator Robert Saleh’s defense have at least stayed within sensible distance of that elite tier had it stayed reasonably healthy? A two-game sample to open the season is admittedly small, but the 49ers’ success out of the gate — especially in contrast to how their defense cratered to end 2024 — cannot be roundly ignored.
It’s at least safe to say this: Given better health, the 49ers certainly wouldn’t have sunk to a ghastly, league-low 20 sacks and a No. 25 defensive EPA ranking by the time 2025 was done — and that’s precisely what makes the injuries so vexing. Even now, in offseason healing time, they’re hurling a wrench into our attempts to analyze just how good this defense — now the third-youngest unit in the league — can be as it enters Year 2 of its renovation.
Bosa and Warner weren’t the only players to sustain major injuries, of course. Williams tore his ACL in Week 9, Collins required shoulder surgery when the season ended, and Yetur Gross-Matos — who scored as an upper-tier interior rusher when available — missed nine games.
But as we zoom in on the D-line, there’s a reason GM John Lynch lamented the loss of Bosa and Williams in particular.
“Certain players … they’re force multipliers,” Lynch said in January. “They make everybody else around them better. And I think Nick was that, and Mykel was just catching on.”
The 49ers hope that Bosa returns to his game-wrecking form in 2026, but the 21-year-old Williams — if he can pick up where he left off — also projects to be vital to the line’s collective success. This past week, Lynch said he expects both to be back for training camp.
Consider how often Williams drew double teams over the first two months of his career.
Then consider the monumental drop-off of the 49ers’ run defense by EPA _after_ Williams got hurt in Week 9. The 49ers ranked No. 6 in run defense EPA before that injury; they tumbled to No. 26 in run defense EPA when Williams was on injured reserve.
There were three leading causes behind the 49ers’ league-low 20 sacks in 2025:• The loss of Bosa, one of the NFL’s top pass rushers.• The health issues of Gross-Matos, because the 49ers were counting on him to be their top interior pass rusher — especially after they drafted Collins and West to initially specialize in run-stopping.
• The deterioration of the run defense, tied to Williams’ exit, which led the 49ers back to their 2024 dilemma: They didn’t have good pass-rushing on late downs since they couldn’t adequately slow the run on early downs.
In Weeks 1 and 2, when everyone was healthy, the 49ers enjoyed high pass-rush win rates (on the Y-axis below) from both of their top edge rushers, Bosa and Bryce Huff. Gross-Matos also posted a top-five win rate among interior rushers.
The line’s positioning on this graph showed a defense that was following its preseason formula to a tee: Williams helped stabilize the run defense and gobbled up double teams, all while multiple pass rushers converged on quarterbacks from advantageous platforms.
But following the injury rash, no one attracted exterior double teams like Williams, and essentially everyone saw their pass-rushing effectiveness dwindle. Huff, who retired last month, saw his win rate dip below the league average after the 49ers had to start using him as a three-down player instead of a pass-down speed specialist — his intended role.
This offseason, then, is about restoring a functional dynamic up front and doing so under Raheem Morris, who has succeeded Saleh as defensive coordinator and possibly even broadened the 49ers’ list of desired traits in defensive ends.
“We’re a four-man front team, but we dabbled in a lot of five-man fronts last year,” Lynch said earlier this offseason. “Raheem’s done a lot more of that because he’s done some 3-4 stuff, so there’ll be some different body types and things, but just small tweaks. The positive thing for me is that it widens the sample size: The guy that wasn’t there because we thought he was more of a 3-4 outside ’backer — maybe there’s a spot for him now.”
The 49ers have done some important work up-front, [trading with the Dallas Cowboys for defensive tackle Osa Odighizuwa](https://sfstandard.com/2026/03/11/osa-odighizuwa-49ers-trade-cowboys/) — they have a bona fide three-down piece on the interior now — and re-signing rotational defensive end Sam Okuayinonu.
But they still need more linemen, especially considering Huff’s retirement and the fact that four projected roster qualifiers are still recovering from surgeries. (Trade acquisition Keion White, a defensive end, was shot in the ankle after the Super Bowl but should be fine in time for next season.)
That’s why the 49ers have been interested in signing veteran defensive end Joey Bosa, Nick’s brother. But at least for now, Bosa’s price tag — he played for about $13 million in Buffalo last season — remains too high.
“I know that would make Mama Bosa happy,” Lynch said at the recent NFL owners’ meetings in Phoenix. “But I don’t know if we can afford him.”
Financial dynamics might change after the NFL Draft this month. The 49ers have invested more draft capital in the D-line than any other team since Lynch and Shanahan have come aboard, so history suggests they’d like to pursue edge-rushing help there.
But it’s impossible to predict how the draft will unfold, especially for a team not slated to pick until No. 27. Perhaps the 49ers’ spending threshold for Joey Bosa or another veteran will increase if they’re unsuccessful in padding the D-line room with promising rookies.
For now, the 49ers are at least satisfied that they’ve acquired Odighizuwa, who nearly notched more pressures himself last season (52) than all of the 49ers’ defensive tackles combined (55).
“Osa is a young, ascending player who we’ve long held in regard,” Lynch said. “We needed that three-technique to come in and disrupt. Osa gives us that.”
Odighizuwa’s addition should allow Collins and West to continue blossoming in their second seasons. They’re run-stoppers by nature and project to become pass rushers by development.
“You can look at Alfred as we did throughout the draft process and say, my goodness, thank you, Lord,” Lynch said. “There is a lot to look at and say, wow, he’s a big, huge man, very well proportioned. He’s athletic. He’s strong. … And when you have that much talent, when you’re coached by a guy like Kris Kocurek and Robert Saleh, if you just listen to him, you’re going to get better.”
West believes improvement is imminent.
“Year 2, I need to have one of the biggest jumps I had in my football career,” he said. “I’m just really bringing my game to the next level, being more dominant in the pass rush, dominating the run even more than I did, affecting the quarterback in different ways.
“You know, pushing the pocket in his face, making him have to roll out so that Nick Bosa can get a sack, so that Mykel Williams can get a sack, or freeing up Alfred Collins. Just changing the game in that way would make a big difference in our scheme and in our team.”
That’s precisely the type of cohesive, unit-wide success that the 49ers had to start off 2025 but couldn’t maintain due to injuries. It was ugly by the end: Run-stopping specialists had to take the majority of pass rushing snaps on the interior while exterior specialists like Huff were forced into foreign three-down roles.
It became impossible to operate a coordinated front that accentuated each lineman’s strengths and hid his weaknesses.
Health will put the 49ers in better position to succeed, but they can’t finish the job without properly tying up loose ends this offseason. That’ll require more D-line acquisitions — through the draft, free agency, or both.
“We’ve got to be better there,” Lynch said. “We understand that. That’s always been at the forefront of our philosophy to make life miserable on opposing quarterbacks and to wreak havoc, and we need to do better there, and we intend on doing that.”