How the Seahawks Defense Shut Down the 49ers Again

Mike Macdonald doesn’t have a double-secret magic coverage that he calls to make it difficult for opposing passing games to function. He doesn’t rely on exotic looks and lots of pre-snap movement.

Instead, the Seahawks predominantly operate out of 2-shell looks and make sure to keep the passing game in front of them. They move after the snap, preventing the quarterback from knowing exactly what the coverage will be until he has the ball in his hands, which slows down the decision-making process.

And most importantly, Seahawks defenders actually cover receivers when playing zone. They understand how to match up to formations and route concepts, and they go where the action is.

On Saturday night against the 49ers, they didn’t allow Kyle Shanahan’s passing game to get off the ground at all. Seattle’s coverage prevented them from doing anything substantial at the deep or intermediate levels. Brock Purdy completed just 2-8 passes for 35 yards on throws more than 10 yards from the line of scrimmage.

The coverage combined with a pass rush that got pressure on over 60% of Purdy’s dropbacks (according to Pro Football Focus) made him uncomfortable from start to finish. He often failed to even set his feet at the top of his drop and was quick to move. That took away his ability to play with any sense of timing, which he relies on to be effective.

With the run game equally as smothered by the Seahawks defense, the Niners were held to just 6 points.

Let’s start with Seattle’s coverage to see how they were able to keep San Francisco from getting anything going on Saturday night.

On this first example, the 49ers had a “Yankee” route concept called with a post from one side of the field and a deep over from the other:

The Seahawks would play quarters coverage and lock up the back-side receiver (Kendrick Bourne) with cornerback Devon Witherspoon: