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The 49ers’ Sustainability Plan Starts on the Defensive Line

San Francisco faces the dual challenges of returning to the Super Bowl while keeping the core of their roster intact

Getty Images/AP/Ringer illustration

The San Francisco 49ers have spent the offseason, essentially, reconstructing last year’s team. It’s hard to argue with that strategy: Last year’s team, if you recall, went to the Super Bowl.

The 49ers were not immune to the salary cap restrictions and contract decisions that require teams to renovate their rosters, but they’ve navigated around them in ways that have not drastically altered the complexion of their roster. The biggest change came along the 49ers’ stacked defensive line: DeForest Buckner, San Francisco’s first-round pick in 2016 who has 28.5 career sacks, was traded to the Colts for the no. 13 pick, which they used to draft South Carolina defensive tackle Javon Kinlaw after trading down one spot.

Trading Buckner as he enters his prime isn’t ideal, but general manager John Lynch wasn’t prepared to give the defensive tackle the contract extension he was seeking; Buckner signed a four-year extension worth $84 million with Indianapolis. Not only did the 49ers land Buckner’s replacement in the trade, but it preserved their cap space, allowing Lynch to keep much of the rest of the roster intact: Defensive end Arik Armstead, safety Jimmie Ward, and key reserves like backup center Ben Garland were all re-signed.

There have been other like-for-like replacement deals: A month after Emmanuel Sanders, who had 502 receiving yards and three touchdowns in 10 games after arriving via trade last October, left in free agency, the 49ers traded up to take Arizona State receiver Brandon Aiyuk, a favorite of head coach Kyle Shanahan at no. 25. Two days later, they traded for Washington left tackle Trent Williams as a replacement for the retiring Joe Staley. Lynch was playing Whack-a-Mole, filling each hole as it popped up.

The 49ers are in this for the long haul. On Monday, they signed Shanahan to a new six-year contract that runs through 2025. It’s reasonable to think Lynch could get a new deal too. Shanahan and Lynch both signed six-year contracts in 2017 when they started in San Francisco with the goal of rebuilding the team together. It’s gone pretty well so far. They’ve been lucky, too, in that defensive coordinator Robert Saleh, however deserving, hasn’t gotten a head coaching job.

It’s about as much stability as a team could ask for. Stability, though, is only useful as a platform on which a team can evolve while addressing its individual needs. Ask the New York Giants, who have been an organizationally stable 51-77 since their last Super Bowl appearance. Teams that stay good remake themselves while holding onto core principles—the Patriots prize versatility, the Seahawks value athleticism, the Chiefs covet speed. The 49ers’ strength is their dominant pass rush; Buckner’s departure illustrates how difficult it is to maintain continuity, but the arrival of Kinlaw, and Armstead’s extension, is a sign they’re up to the challenge. How they go about meeting it will be part of a conversation about the comparative values of investing in coverage and pass rush that’s playing out around the NFL.

Last season, Saleh’s defensive line put pressure on opposing quarterbacks on 28.7 percent of their dropbacks, second in the league behind the Steelers. They were fifth in the league by sack total (48) and second in Football Outsiders’ adjusted sack rate, also behind Pittsburgh. As a whole, the defense finished eighth in scoring and second in yards and yards per play allowed.

It’s unfair to expect Kinlaw in Year 1 to be where Buckner was in Year 4, but he can help the 49ers’ run defense. They allowed 4.5 yards per rush last season, tied for 22nd in the NFL, and it stands to reason the 6-foot-5, 319-pound Kinlaw could be better than the 6-foot-7, 287-pound Buckner at filling those lanes. Whatever dropoff in pass rush they might expect from Buckner’s absence could also be made up for by second-year defensive end Nick Bosa’s potential growth. Bosa had 80 total pressures as a rookie, according to Pro Football Focus. He earned PFF’s fourth-highest grade for a rookie edge defender who averaged 15 snaps per game or more since the company started charting in 2006. The only players to finish higher were Aldon Smith, Von Miller, and Khalil Mack. Nick Bosa finished just ahead of his brother, Joey.

Bosa should have solid talent around him for the next few years. Armstead and Kinlaw are under contract through 2024; edge rusher Dee Ford, like Bosa, is signed through 2023. This is all bad news for NFC West quarterbacks, but good news for the 49ers secondary: San Francisco had PFF’s second-highest overall team coverage grade in 2019 and was seventh in the league by holding opposing quarterbacks to a 61.3 percent completion rate. By pairing their pass rush with mostly zone defense on the back end, the 49ers disrupted timing, forced quick throws, and limited big plays. San Francisco defenders faced the lowest depth of target in the NFL last season and allowed the fewest total air yards. Saleh ran his own version of the defense he learned under Gus Bradley in Seattle and then Jacksonville, and, fittingly, had Richard Sherman turning in an excellent season at cornerback as part of it. Quarterbacks throwing at Sherman last season had a passer rating of 46.8.

The future of that secondary, though, is less clearly defined than that of the defensive line. Sherman will be 32 this season and is entering a contract year. Nickel corner K’Waun Williams will also be a free agent next offseason. It’s not clear yet how Lynch will address those situations. There were no upgrades in the secondary: Players like Ahkello Witherspoon, who was benched during the playoffs last year, return, as will Jason Verrett, who was re-signed. Verrett has played six games since 2015, and last season gave up a 32-yard defensive pass interference penalty and a 39-yard touchdown in two of his four defensive snaps.

Right now, the 49ers are challenging the conventional wisdom of prioritizing pass rush over pass coverage. The Patriots and Ravens, two of last season’s best defenses, finished first and fourth respectively in Football Outsiders’ pass defense DVOA while spending the highest percentages of the salary cap on their secondaries and among the lowest on edge defenders. Other teams are following suit: The Dolphins made Byron Jones the highest-paid corner in the NFL this offseason, the Bucs drafted coverage players with their four highest picks in 2019, and a year later, they went all-in by signing Tom Brady. The Chiefs won the Super Bowl because of Patrick Mahomes and their offense, but their offseason additions of cornerback Bashaud Breeland and safety Tyrann Mathieu stabilized a defense that kept them from getting there a year earlier.

The money tells a different story in San Francisco. They’re the seventh-highest spenders in the NFL both on their defensive line and on their secondary, but they’ve been able to control costs on the defensive line by investing five first-round picks in the last six drafts there; much of the cost in their secondary comes via Sherman’s contract. In 2020, four edge rushers, as well as defensive lineman Solomon Thomas, will count for more than $4.5 million against the salary cap. Only two players in the secondary—Sherman and safety Jaquiski Tartt—hit that threshold.

The 49ers have $15.5 million in current salary cap space, according to NFLPA records, but most of that would be taken up by a new deal for tight end George Kittle if the 49ers want to avoid having him hit free agency when his rookie contract runs out after this season. Spotrac projects they’ll have $44.6 million, middle of the pack, next offseason.

The simple, unsatisfying answer for what teams need to do when they’re in the enviable but delicate position of having good players who deserve big contracts is to hit on some draft picks. San Francisco doesn’t have the luxury of taking a bunch of swings: After their two first-round selections they didn’t pick again until the fifth round of this year’s draft. The 49ers also gave up their third-round selection next season as part of the trade for Trent Williams.

When resources become scarce, how teams allocate them becomes more telling. The 49ers built one of the best units in football, and made a Super Bowl, by prioritizing their defensive line. Now, they face the dual challenges of trying to get back to that game while keeping the core of their team together. Whether they succeed or fail, they’ll be an interesting test case in how to creatively ensure continuity while competing at the highest level.