For the 49ers, Sunday’s game in Seattle is so big it could be a Week 5 game. First place in the NFC West is on the line, and if the Niners can win it, they’ll have a multi-game lead in the division with back-to-back wins over the Rams and Seahawks. That’s a nice little cushion in the race for the league’s most competitive division.
San Francisco-Seattle matchups are always bittersweet, but the 49ers carry an extra layer of resentment into this tilt after last season’s end, with the Seahawks’ defense shutting down their offense in a locker twice in three weeks, including a 41-6 drubbing in the NFC divisional round.
It probably means a little more to 49ers coach Kyle Shanahan and quarterback Brock Purdy, who have spent the last few years tearing up defenses but always seem to struggle against Seahawks coach Mike MacDonald.
In their first game, when MacDonald was looking for plays for Baltimore’s defense, Purdy threw four interceptions in a 33-19 loss on Christmas night that ended his MVP campaign in 2023. Shanahan and Purdy got revenge against MacDonald in their first cross-divisional game, a 36-24 win at No. 24. He hasn’t scored more than 17 points in any of the four games since. Three of those were losses, and San Francisco has not scored a touchdown in either of the last two.
Macdonald has been Shanahan and Purdy’s boogeyman for the past few years. With him coaching a division rival, they can’t escape them.
For the 49ers to take control of the NFC West (and the conference overall), for Shanahan to prove he’s still the league’s best offensive mind, and for Purdy to firmly establish himself in this year’s MVP race, they’ll have to get past Macdonald first.
So… can they do it?
Before we can try to answer that, let’s look at why Macdonald’s defense has been an intractable puzzle for Shanahan and Purdy. For a theory, let’s go directly to one of the main sources:
“(It’s) how fat they are, but (they’re) still aggressive,” Shanahan said this week. “When they’re aggressive, they’re rarely irresponsible. It’s hard to get big plays against them. I think they’ve been No. 1 in the league two years in a row in that, whether it’s the run game or the pass game.”
Shanahan is right. No defense has been better at limiting explosive plays over the past two seasons. And the way they do it makes playing against the Seahawks defense such a miserable experience.
“They play more of a two-shell defense than anybody in the league.” Shanahan said. “Even when you go through the top seven, it’s hard to get past those safeties. Those safeties back everybody up for big plays — they’re still very aggressive, though, so it’s not like you can choke and choke them all game long.”
Macdonald has built her defense in a way that allows her to enjoy all the benefits of a crouch-but-don’t-break approach, without one key difference: this defense doesn’t give her opponents any room to breathe.
Seahawks area game coverage offers the best of both worlds. The tough, double-height zone shell prevents over-the-top shots, but the “match” element allows defenders to stay firmly in the lane. Even to a trained eye, it can be hard to tell if Seattle is in man coverage or zone coverage. On any given pass, it looks like they’re playing both.
Seattle’s defensive approach is particularly effective at taking away the middle of the field and up the layers. This is where the linebackers and safeties sit, looking to pick off receivers entering their designated zones. Windows close pretty quickly against Seattle.
A key to San Francisco’s continued offensive success is Shanahan’s ability to open those windows with his play patterns. Purdy has been a great fit in the scheme because he is willing and able to make those throws, which can be difficult for quarterbacks who lack wing talent. Purdy may not have a 100 mph fastball, but he throws with anticipation — which buys him a few splits of a second — and he can feather over defenders.
Shanahan makes good use of Purdy’s talents by calling many high-low concepts up the middle. He’ll have one receiver run a short route about 5 yards deep, with another receiver running a deeper route that breaks or bends behind him 10 to 15 yards downfield.
Shanahan is a master at sending the same concepts over and over, but from different formations and personnel groupings to keep the defense off his scent. Against 30 other teams, Purdy can stain that zone all game long. Since the start of the 2025 season, about a quarter of his attempts have been aimed at the small area between the numbers five to 20 meters downfield. Here’s his pass map with that area of the field highlighted.
Courtesy of Pro Football Focus.
In the three games he’s played against Seattle, only about 12% of his attempts have targeted the same zone.
Courtesy of Pro Football Focus.
And the difference in production is staggering. Per Pro Football Focus, Purdy averaged 5.8 yards per attempt and -0.88 expected points added per game against Seattle. He averages 9.7 yards per attempt and 0.45 EPA per game. Even when those throws have been available, the Seahawks have made them ineffective.
In three games against Seattle last season, Purdy averaged 5.8 yards per attempt on plays where he remained “in structure.” That’s nearly 3 yards lower than his average against any other opponent. With Shanahan’s offense failing him — and his team on the scoreboard — Purdy went into scrimmage mode, which … didn’t work out too well either. The 49ers are not a team built for a heavy passing game. They can do it when needed, but it’s not their goal offensively, and Seattle makes it difficult to play that type of game.
Brock Purdy and the 49ers were dominated in the NFC Divisional Round by the Seahawks earlier this year. (Sean M. Haffey/Getty Images)
San Francisco didn’t score a touchdown over the final 120 minutes against Macdonald’s defense last season, so Shanahan and Purdy will want to avoid falling into that trap again. But the first game offers a solid path to success for the offense.
The Niners won that game, and while they only put 17 on the board, the offense moved the ball. They only punted twice, but Purdy dropped two passes (trying to force it up the middle), and Jake Moody missed two field goals (one blocked).
Despite the interceptions, Purdy finished with an 85.5 QBR. It was his third-highest mark of the season and his second-best performance against a Macdonald defense.
Shanahan’s running game wasn’t very efficient, but it wasn’t completely useless. The 49ers didn’t have to give up the run at any point — the running backs tallied 31 carries — allowing the offense to stay on script. Using a shotgun in San Francisco is a good health indicator for the offense.
When San Francisco uses the shotgun in more than 80% of the games, as was the case in the two losses to Seattle and Purdy’s three-pick game against Carolina, things are not going well. When it’s 75% or lower, the offense is usually humming. Purdy was in the “gun” for just 74% of his losses in that Week 1 win. It was also 74% in the 2024 win, when the 49ers dropped 30 on Macdonald’s defense, before reaching his final form.
Based on how the 49ers operate in 2026, Shanahan will want that number even lower on Sunday. The veteran of the game has added several new tricks, and most of them feature Purdy under center.
Shanahan has really spruced up his running game, with new moves and alignments. It’s a nice mix of old school looks with modern features. On this play, fullback Kyle Juszczyk moves into an old split back look just as the ball is snapped, and then the 49ers run an old counter concept that could have been lifted from the Bill Walsh playbook.
Younger coaches like the Bears’ Ben Johnson, Liam Coen and Klayton Adams have pushed creativity forward, and Shanahan isn’t far behind. He might be content with his A Million Different Ways to Run Outside Zone game, which had always worked for him, but he knows smart defensive coordinators like Macdonald are always adapting.
The defense run by Macdonald has evolved since his first season in Seattle. The loss to San Francisco may have been one of the turning points. The 49ers rushed for 228 yards and exposed several holes in the Seahawks’ running front. Macdonald patched them up with runs to plug the gaps that offenses were trying to attack. Here’s an example from the opener.
What looks like an attractive bubble of space C before the moment…
… is closed behind him by a powerful defender.
In 2024, Macdonald’s first season, Seattle called blitzes on 13% of first plays, according to Pro Football Focus. Last season, that number jumped to 23%, and is up to nearly 30% in 2026.
Sunday’s chess match between Shanahan and Macdonald will begin in the trenches. The 49ers coach will look for soft spots up front to exploit with the run. Macdonald will try to hide those soft spots as best he can. It’s like a game of Battleship played with 300-pound athletes instead of tiny pieces of plastic.
If Shanahan can win that game within the game, Purdy should be at his best and primed for another monster game, cementing his place as the front-runner for MVP. More importantly, the 49ers would have carved out a two-game lead in the division and established themselves as the NFC’s best team.
