Brock Purdy is rolling into Week 5 with numbers that don’t look real, and now the 49ers quarterback gets the kind of test that can tell you exactly how real they are.
Through four games of San Francisco’s 4-0 start to the 2026 season, Purdy has built a statistical résumé that stands alone. He is the only quarterback in NFL history to begin 4-0 with one or fewer sacks, fumbles or interceptions combined, according to CBS Sports Research.
He also leads the league in passer rating (126.2), passing success rate (61.9%) and expected points added (EPA) per dropback (0.53), while sharing the lead in passing touchdowns (11). His 0.53 EPA per dropback is the second-best mark through four games in the 21st century, trailing only Tom Brady’s 0.59 in New England’s 16-0 2007 regular season.
On top of that, Purdy ranks fifth in completion percentage at 69.9%.
Now comes the hard part.
San Francisco heads to Lumen Field to face the defending Super Bowl champion Seahawks in a game that pairs the NFL’s most efficient offense by yards per play (6.8) with the league’s stingiest defense in that category (4.0). And if recent history means anything, Seattle has had the upper hand when these two teams collide.
In Week 18 of the 2025 season, with the NFC West title and the conference’s No. 1 seed on the line, Mike Macdonald’s “Dark Side” defense buried Kyle Shanahan, Purdy and the 49ers in a 13-3 win. That was San Francisco’s lowest point total since Week 1 of the 2017 season, Shanahan’s first game as the 49ers’ head coach.
Then in January, the Seahawks flattened San Francisco again in the NFC divisional round, a 41-6 rout at Lumen Field that started with Rashid Shaheed bringing the opening kickoff back for a touchdown. The 35-point margin tied the largest playoff victory in Seahawks history.
Seattle’s defense has kept that same bite this season. The Seahawks are allowing the fifth-fewest points per game (18.3), the fewest total yards per game (246.8), the fewest yards per play (4.0) and the fewest passing yards per game (144.8), while tying for the league lead in interceptions with six. If this pace holds, they’d become the first team since the 2013-14 Seahawks to finish first in total defense in consecutive seasons.
So where does this matchup tilt? A big chunk of it comes on early downs.
Purdy has been lethal when San Francisco is passing early in the down-and-distance sequence. He leads the NFL in EPA per dropback on early downs at 0.50 and is tied for the league lead with seven touchdown passes in those situations.
He’s also operating from clean pockets far too often for defenses to be comfortable: Purdy has faced pressure on only 24.7% of early-down dropbacks, the lowest rate in the league, according to TruMedia. When he’s clean on those snaps, he’s averaging 9.6 yards per attempt, the third-best figure in the NFL, per Next Gen Stats.
Seattle, though, has been built to disrupt exactly that kind of rhythm. The Seahawks own the second-highest early-down pressure rate in the league at 44.2% despite blitzing at the second-lowest rate in those situations, 17.9%, per TruMedia.
That’s the key detail here: they’re getting home with the front four. Only the Vikings pressure more on early downs, and Minnesota is blitzing at a much higher rate.
The pressure has come from multiple places. Edge rusher Uchenna Nwosu has an early-down pressure rate of 22.2%, edge rusher DeMarcus Lawrence sits at 15.5% and defensive tackle Leonard Williams is at 14.8%, with all three ranking inside the top 25 individually entering Week 5, per TruMedia.
That means a lot is about to fall on Trent Williams and the rest of the San Francisco offensive line. The 38-year-old, 12-time Pro Bowl left tackle has seen the Seahawks bother him a little more than most teams since Macdonald took over in 2024.
In four combined matchups with Seattle’s defense, including the playoffs, Williams has allowed 12 pressures without a sack on 143 pass-blocking snaps, an 8.4% pressure rate. That compares with an 8.1% rate against all other opponents over the last three seasons, per Next Gen Stats.
Half of those 12 pressures came against Boye Mafe, who is now with the Cincinnati Bengals after leaving in free agency this past offseason. Lawrence is the only other Seahawks defender with multiple pressures against Williams in the Macdonald era, collecting two.
Purdy’s career line against Macdonald’s Seahawks since 2024, including the playoffs, tells the same story: a 2-3 record, 15.8 points per game, 6.6 yards per attempt, six touchdowns and five interceptions, an 85.9 passer rating and eight sacks.
Still, one of the most important things any offense can do against a defense like Seattle’s is avoid self-inflicted damage, and that’s been a Purdy specialty through four games. As a team, the 49ers have the lowest rate of plays that lose yards through the first four games of a season in the 21st century, excluding kneel downs, at 2.2%, according to CBS Sports Research. Purdy himself has the lowest negative play rate by any quarterback through four games this century at 0.8%.
That’s the real edge in this matchup: San Francisco’s precision against Seattle’s pressure. Shanahan and Purdy versus Macdonald and the “Dark Side” is set up as the headliner of Week 5.
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