Seattle’s secondary tests San Francisco’s perfect start

A division test

The San Francisco 49ers bring a 4-0 record into a meeting with the 3-1 Seattle Seahawks on Sunday, October 11, and the game turns on whether Seattle’s pass defense can slow the league’s most productive aerial attack. It is a matchup between two NFC West teams that have won with different strengths: San Francisco’s offense has surged, while Seattle has made opponents work for every clean throw.

The 49ers are averaging 30.5 points, 2nd in the NFL, and Seattle is allowing 18.3, 5th. San Francisco has protected the quarterback especially well, allowing no sacks through four games, but Seattle’s defense has generated three takeaways per game, tied for 2nd in the league.

The passing-game collision

San Francisco enters with the NFL’s No. 1 pass offense by efficiency, against a Seattle pass defense ranked 3rd. EPA measures expected points added on each play, and the 49ers have produced 0.156 EPA per play; Seattle has allowed minus-0.125, the 2nd-best defensive mark.

Brock Purdy has thrown for 1,007 yards with 11 touchdowns and one interception in his four starts. His clearest test is a secondary allowing just 161.3 passing yards per game, 2nd in the league, while George Kittle has already supplied 244 receiving yards and four touchdowns.

Seattle can answer through Jaxon Smith-Njigba, whose 481 receiving yards and six touchdowns lead its passing game. The 49ers rank 5th in pass defense by efficiency, but their 1.8 sacks per game rank 23rd, putting more weight on coverage against Sam Darnold and a Seahawks offense ranked 9th through the air.

Availability and setting

The 49ers will be without defensive end Nick Bosa and wide receiver Brandon Aiyuk, thinning both the pass rush and receiving group. Cornerback Upton Stout is questionable with a shoulder injury, while three other San Francisco players are out.

Seattle is without cornerbacks Julian Neal and Terrion Arnold, and running back George Holani is questionable with ribs and knee injuries. Two other Seahawks are out, leaving the secondary’s depth central against Purdy’s receivers.

The game is at Lumen Field in Seattle on Sunday, October 11, at 4:25 PM ET. Sportsbooks’ prices give Seattle a 60% chance to win.