The Rise of a New Legion of Boom

Back in the day, from 2012 through 2015, when the Seattle Seahawks led the NFL in scoring defense in every one of those seasons, it was the Legion of Boom that made history with one of the most formidable defensive units in NFL annals. Now, in 2025, Seattle’s “Black Hole” defense under second-year head coach Mike Macdonald appears to be every bit as dangerous.

As the LOB did so often, this new defense stepped up emphatically when it was needed the most. In Saturday night’s game against the San Francisco 49ers, the NFC’s one-seed was at stake, with the loser of the game dropping to wild-card status. The 49ers’ offense had been riding high with a healthy Brock Purdy at quarterback, and running back Christian McCaffrey playing at an MVP level, but against this particular black hole, that offense was entirely negated.

A Defensive Masterclass

The 49ers had just nine first downs — their previous low this season was 12 against the Houston Texans in Week 8. Kyle Shanahan’s offense gained just 173 total yards, which was not only their fewest this season, but the second-fewest in Shanahan’s time as the team’s head coach, which goes back to 2017. The only other defense to limit the 49ers to fewer yards in the Shanahan era belonged to the Philadelphia Eagles, who allowed 164 yards in the 2022 NFC Championship game.

This Seahawks defense has been getting better and better all season long, and it seemed that everything the 49ers do best, they had a ready answer to snuff it out. San Francisco came into this game with an EPA per play of +0.26 on third down, second-best in the NFL behind the Green Bay Packers’ +0.27. But Seattle’s defense had allowed an EPA per play of -0.36, by far the lowest in the NFL. That played out, as the 49ers converted two of nine third-down attempts, and went three-and-out on three of their eight drives.

Stifling the 49ers’ Star Power

As for McCaffrey, who gained just 23 yards on eight carries, he was going up against a Seattle defense that had allowed a rushing EPA per play this season of -0.38, which basically means that opposing running backs have been better off fumbling or throwing the ball out of bounds than trying to deal with the Seahawks’ front sixes — because the Seahawks didn’t need front sevens, per se.

That Seattle’s defense was able to play at this level against such an opponent wasn’t necessarily a surprise, but neither would it have been a shock if San Francisco had done enough to make the game at least a bit more competitive than the 13-3 final score indicated.

But in truth, this could have been far more of a blowout. The Seahawks blew a fourth-down attempt from the San Francisco four-yard line with 7:27 left in the first quarter, and kicker Jason Myers missed two field goals. Quarterback Sam Darnold, who continued to look jittery and too quick in and out of the pocket when pressured, completed 20 passes in 26 attempts for 198 yards, no touchdowns, no interceptions, and a passer rating of 97.9.

Turning Point in the Fourth Quarter

What Darnold didn’t do was give away the ball, and the one time the 49ers did that, it was a major decider in the result. The 49ers were finally making gains on Seattle’s defense at the start of the fourth quarter with a drive that got them down to the Seattle six-yard line, and then, everything fell apart again. Purdy threw a quick pass to McCaffrey, who couldn’t hold onto the ball, and Seahawks linebacker Drake Thomas was there for the win.

Purdy didn’t play horribly considering what he was up against — he completed 19 of 27 passes for 127 yards, no touchdowns, that one interception, and a passer rating of 64.9 — but that’s also the standard this Seattle defense has set. If the quarterback survives the experience, give him a gold star. Purdy almost didn’t.

While he was pressured on just 34.4% of dropbacks per Next Gen Stats, Purdy completed three of seven passes for 25 yards when he was disrupted, compared to 16 of 20 for 102 yards and the interception when not pressured. More remarkably, Purdy attempted no deep passes in the game, marking his only contest in the 2025 season without a deep attempt. Instead, he passed under 10 air yards on 74.1% of his attempts, completing 15 of 20 such passes for 65 yards and again, that interception.

A Strong Run Game Helps Seal the Win

Where Seattle’s offense really showed up here was in the run game, which had been an issue for the Seahawks through most of the season. Zach Charbonnet gained 74 yards and scored a touchdown on 17 carries, and Kenneth Walker gained 97 yards on his 16 carries, including a 19-yard run on third-and-17 with 3:48 left in the game that basically allowed Seattle to end the contest by running out the clock.

“It’s something we’ve definitely been working on in the second half of the season, and we’ve just done a great job,” running back Zach Charbonnet told ESPN’s Scott Van Pelt postgame. “Receivers, tight ends, O-line, and everyone up front, and the running backs just doing our jobs, too. It’s definitely nice to play complementary football.”

A Defense That Speaks Volumes

It is, but the story here was a defense just as constricting as any the Emerald City has ever seen. Quite a statement given how the Legion of Boom set the tone more than a decade ago, but the results speak for themselves. And now, for the fourth time in franchise history, the NFC postseason will go through Seattle. In the three previous times this happened (2005, 2013, 2014), the Seahawks made it to the Super Bowl every time.

It might be time to book those plane tickets to the Bay Area for Super Bowl XL, Seahawks fans.