Seattle's defensive depth will be tested in stopping 49ers' offense

RENTON, Wash. — The Seahawks haven’t matched up well with the San Francisco 49ers over the last two years, which is why Seattle’s average margin of defeat during this 5-game losing streak against its divisional rival is 15.2 points.

The reigning conference champs come to Seattle on Thursday night with a 2-3 record and seemingly more vulnerable than they’ve been in previous meetings with the Seahawks. But the first NFC West game of head coach Mike Macdonald’s career will nonetheless test whether his defense has what it takes to compete with one of the NFL’s best play callers.

The Seahawks had the best defense in the league by EPA per play through the first three weeks of the season (all stats provided by TruMedia unless stated otherwise). They pressured the quarterback as well as anyone and were solid against run outside of a shaky second half against New England in Week 2. The last two weeks have been a fall from grace.

In consecutive losses to the Detroit Lions and New York Giants, Seattle’s defense has allowed 65 points; only the Carolina Panthers have allowed more (70). In those two losses, Seattle’s opponents have rushed for 289 yards on designed attempts, the sixth-most over the last couple of weeks. The Seahawks have surrendered explosive pass plays at a league-high rate and have allowed opponents to convert third downs 45.5 percent of the time, which if sustained for an entire season would be one of the 10 worst marks in the league.

Despite their losing record, the 49ers have the firepower to cause problems for the Seahawks, specifically in the run game. Macdonald’s defense uses a variety of coverages each week but most of the time they’re operating out of a split-safety look before the snap. Defending the run from that safety structure can be difficult because not every gap is accounted for up front. There’s stress on the second-level defenders to work in concert with the defensive line, track the ball and limit explosive runs. They haven’t delivered.

“We’re not leveraging the ball well on the second level as well as we need to be,” Macdonald said during a KIRO-AM radio interview this week. “For the most part, our interior guys are fighting their tails off. Our edge (defenders) are, for the most part, playing pretty well. The second level run fits right now are falling short.”

San Francisco has been without All-Pro running back Christian McCaffrey all year, but head coach Kyle Shanahan has successfully leaned on Jordan Mason to spearhead the running game. Mason has 536 rushing yards, second only to Baltimore’s Derrick Henry. Mason’s 25 first-down runs are the fifth-most in the league and more than Kenneth Walker III and Zach Charbonnet combined (19). Receiver Deebo Samuel has only 36 rushing yards on 15 carries with one touchdown, but the Seahawks know he’s a big-play threat whenever he touches the ball. Shanahan is known for his work with quarterbacks. Still, defensive coaches like Macdonald know he builds everything off the run game, which consistently puts defenders in conflict and exploits missed tackles and bad angles.

“It’s NFL run schemes that we’ve seen and we’ve had success against, and some schemes that we’ve had a hard time with up to this point,” Macdonald said. “We’ve gotta go play ball. We’ve gotta go fight our tails off and be on the same page and get 11 hats to the football for as many plays as it takes and try to come out with a win. That’s the name of the game. That’s the NFL for you. That’s when you go up against the 49ers. Our guys know we’re in for that, and we’re up for the challenge.”

Injuries may require Seattle to play without outside linebackers Derick Hall (foot), Boye Mafe (knee) and Uchenna Nwosu, who has already been ruled out by Macdonald because of a thigh injury sustained on Sunday and is expected to be placed on injured reserve (all Seattle’s practices this week are walk-throughs so the participation listings are merely estimations). Macdonald also ruled out rookie defensive tackle Byron Murphy II, who suffered a hamstring injury in Week 3. Missing all those edge defenders would increase the burden on Seattle’s second-level players to be better against the run. The second level primarily consists of inside linebackers Tyrel Dodson and Jerome Baker but also includes safeties Rayshawn Jenkins, Julian Love and K’Von Wallace, as well as nickel Devon Witherspoon.

One of the adjustments teams make out of a split-safety structure is bringing one of the safeties near the line of scrimmage to make sure every gap is accounted for. The tradeoff is leaving the cornerbacks alone on the outside, a notable move considering the Seahawks will likely be without cornerback Riq Woolen, who sprained his ankle against the Giants.

Woolen’s coverage has been excellent to start the season. He has allowed only five catches (on 12 targets) for 41 yards with one interception as the nearest defender in coverage, according to Next Gen Stats. Playing without Woolen could mean more snaps out for Tre Brown, who is coming off his worst game as a pro. He allowed six catches for 100 yards and a touchdown, all to Giants receiver Darius Slayton. Brown was also twice flagged for holding.

Brown, who had only allowed 69 yards on the season before Week 5, chalked up Sunday’s performance to the highs and lows that come with playing corner in the NFL. He said he’s “feeling good” heading into Week 6 and anticipates the 49ers trying to come at him just like the Giants did.

“I hope that happens because I know one thing about me, I’ll always bounce back,” Brown said. “I’ve shown that. The awareness I have, I know they’re gonna come and try to attack me because they think I’m sweet. I invite that.”

On Sunday, Woolen was replaced by fifth-round rookie Nehemiah Pritchett. He was targeted four times in nine coverage snaps with three of those passes coming on third down. Daniel Jones completed 2 of 4 passes for 22 yards and a pair of first downs. His fourth attempt was a third-and-4 slant to Slayton that Pritchett knocked away, giving the ball back to Seattle’s offense late in the fourth quarter to set up a potential game-winning drive. That was Seattle’s only pass breakup in the last two games.

Pritchett said he anticipated being targeted immediately upon entering the game for Woolen because he’s a rookie. He also figured a double move would come at some point, which is what happened on third-and-11 late in the third quarter when Slayton tried to beat him with a slant-and-go route in the end zone (the ball sailed out of bounds). Pritchett expects more action on Thursday night.

“I feel like all teams are going to do that,” Pritchett said. “It is what is. I’ll be ready.”

On top of getting quality cornerback play on Thursday, the Seahawks must be much better than they have been in recent weeks defending play-action passes. Lions QB Jared Goff went 12-for-12 for 229 yards and with one touchdown on play-action passes in Week 4. Dre’Mont Jones’ late-game sack that ended in a safety was Goff’s only negative play on a play-action dropback. Daniel Jones went 9-for-12 for 101 yards with two touchdowns on 14 play-action dropbacks. He was sacked once.

San Francisco quarterback Brock Purdy leads the league in dropback EPA when using play action.

None of this is new to the Seahawks, of course. They’ve seen plenty of Purdy since he became the starter in the back half of his rookie season. In four wins over Seattle, he’s completing 66.4 percent of his passes while averaging 281.5 yards with eight touchdowns and just two interceptions. When nine-year veteran defensive tackle Jarran Reed was asked how San Francisco’s offensive scheme has evolved in recent years, he quickly replied, “It hasn’t changed.”

“All they do is run, run, run, and then they go play action,” Reed said. “Then they drop back a little bit and throw the ball. I think quarterback play has changed a little bit but it’s basically the same thing I’ve seen for the past couple years.”

The Seahawks’ plan to stop that scheme starts with the area of the game that has been killing them in recent weeks.

“We’ve got to stop the run first,” Reed said.