Can the 49ers defense be elite again? What it's doing to improve in 2024 (2024)

After regressing last season, the San Francisco 49ers will try to get back to playing at an elite level defensively, but because of their salary cap situation with impending contracts for offensive stars, they don’t have much choice but to improve from within. They’ll have largely the same defensive roster —though impacted by linebacker Dre Greenlaw expected to miss a significant chunk of the season due to the Achilles injury he suffered in the Super Bowl — but the team hopes it can return to playing elite with better coaching and being a more connected unit.

San Francisco’s defense played at a near-historic level in 2022. It topped the league in defensive EPA per play and allowed the fewest points per drive (1.42). In the following offseason, defensive coordinator DeMeco Ryans left to become the Houston Texans’ head coach and the 49ers hired veteran coach Steve Wilks to replace him. They hoped Wilks could continue their preferred scheme, which they’d been very successful with under Robert Saleh and Ryans, but the defense regressed.

The 49ers ranked 12th in defensive EPA per play and eighth in points per drive (1.67) in 2023. They were still a very good defense by most metrics, but they had lapses at inopportune times and their biggest drop-off was against the run. They finished 28th in defensive rushing success rate last season. Defensive lineman Arik Armstead has been one of the pillars of their run defense, but he left in free agency. They’ll mitigate his loss with solid free-agent additions like defensive tackle Maliek Collins and end Leonard Floyd. Neither is a superstar, but they should provide consistent high-level play.

The 49ers again hope that better coaching will make the biggest impact. After firing Wilks, instead of looking outward for a new defensive coordinator, Kyle Shanahan promoted defensive backs coach Nick Sorensen to defensive coordinator and hired Brandon Staley, giving him a unique title: assistant head coach-defense. Sorensen will help the 49ers get back to doing some of the things they’ve had success with in the past while Staley will offer a fresh perspective and introduce new ideas.

Emphasis on connecting the front to the secondary

There seemed to be a disconnect last season between the front and secondary. One of the 49ers’ defensive staff’s biggest goals this offseason is to get them to play like a more connected unit against the run and pass.

A staple of the 49ers defense is a single-gap attacking defensive line that gets upfield. Last season, offenses came in with highly specialized game plans with runs like traps, crack tosses and fly sweeps that took advantage of that aggressiveness. The 49ers never were able to stabilize against those types of runs, but they’ve looked into it extensively this offseason.

“There are technical aspects that we have to look into to get better with it, especially the crack toss plays on the perimeter. We’ve always gotten traps just because of the nature of our defense, and I think (defensive tackle) Kevin Givens and some of our other dudes this year played the trap well,” 49ers defensive line coach Kris Kocurek said. “But then just the perimeter crack tosses, from a technical aspect and all levels of the defense, they’re small, minute things that we can see, recognize and try to put our guys in a better position technically to play that. And then there’s a schematics side of it also, recognizing the formation, being able to adjust to the formation that we’re seeing those perimeter runs out of and trying to get more population to the football on the perimeter.”

With perimeter runs, the front has to be able to disrupt the ball carrier and slow the ball down for the secondary to come up and help. And in some situations, members of the secondary are key parts of the run fit. Finding stability at nickel cornerback should help. Last season, Deommodore Lenoir cycled inside and outside situationally because he could do both at a high level. Depending on who emerges as a starter this season, the hope is that Lenoir can stay in one spot. Rookie Renardo Green, who played mostly outside at Florida State, has gotten reps at nickel in OTAs.

“You gotta understand the front so you can understand your run fit at level two,” 49ers secondary coach Daniel Bullocks said. “So if I’m at nickel, if it’s Renardo Green or Deommodore Lenoir inside, he gotta understand the front. Most times, we all are in a front with the wide nine to the tight end side. So you gotta understand the front mechanics so you can know your fit versus the run, so we won’t get gashed for an explosive play in regards to that. Sometimes (Sorensen) can tag a different call that allows him to line the stunt a different way so your gap can change based off the call.”

Bullocks says they’ve been reviewing the front mechanics and different calls up front daily so that the secondary completely understands how the front affects their jobs. He also emphasized the importance of knowing their weak spots in certain pressures.

The 49ers didn’t do much to bolster the secondary other than drafting Green. Playing as a more connected unit will be essential for improvement against the run and pass.

How will Brandon Staley help?

Staley comes from the Vic Fangio tree, and Fangio’s defensive principles are very different from the 49ers’ style of play. His system is an odd front with defensive linemen responsible for playing a gap-and-half, which is more passive than what the 49ers ask their defensive line to do. Kocurek made it clear that the 49ers will not implement those techniques with what they do.

“We play our front the way we play it,” Kocurek said. “So we’re still gonna be an attacking nine-technique, three-technique, two penetrating fronts. You may see various different types of fronts, which we’ve installed throughout the years, different types of bear fronts, and maybe an under front here and there, and just to keep people honest with our alignments. But we’ve committed to an attack front, we’re gonna be attacking up front.”

The 49ers will mix in some more odd front looks and be a little more exotic in their presentation, but they’ll be attacking upfield in those looks. So Staley will have some influence in that area, but where his impact will be felt most is on the secondary. Bullocks said Staley can add to their coverage menu off of those fronts. Interestingly enough, Staley and several assistants said he also helps them understand how offenses will want to attack them.

“Just from his eyes alone, he sees it from an offense standpoint, he understands how we operate on the defense standpoint,” Bullocks said. “So, he looks at it like, how can offense attack us? So, that’s been kind of big for us.”

Brandon Staley's most revelatory answer might've come when he shared his connection with Mike Shanahan, which dates back to before him joining the 49ers… pic.twitter.com/BPrU4FElnS

— David Lombardi (@LombardiHimself) May 23, 2024

The 49ers have evolved and have increasingly mixed in more quarters (four deep) coverage with their base Cover 3. They played quarters last season at the third-highest rate in the league (22.1 percent). Staley’s defenses with the Rams and Chargers majored in two-deep coverages that included quarters, so he can also help add to their quarters playbook.

“If we need to make more adjustments in quarters, how can we make those adjustments?” Bullocks said. “Maybe just smaller tweaks here and there to Cover 3 or 5. So, just (Staley’s) expertise and knowledge in that area right there can allow me to evolve more.”

Going back to their schematic roots with Sorensen while balancing fresh ideas and tweaks from Staley will be the formula that the 49ers hope gets their defense back to being elite. It’s a unique arrangement that seems sound in theory.

(Top photo of Renardo Green at OTAs: Jeff Chiu / Associated Press)

Ted Nguyen is a NFL staff writer for The Athletic. He breaks down film to uncover the story that the X's and O's tell. He also covers the latest trends around the league and covers the draft. Follow Ted on Twitter @FB_FilmAnalysis