49ers-Seahawks preview and prediction: Can Brock Purdy and Kyle Shanahan finish off an improbable regular season with a win?

We’re nearly two months removed from the San Francisco 49ers allowing 42 points at home to the then Super Bowl favorite Los Angeles Rams. The result dropped the Niners to just one game over .500, leaving many fans skeptical about a playoff berth.

That was Week 10. We’re heading into the final week of the season, and not only do the 49ers have one more win than the Rams, but Kyle Shanahan, not Sean McVay, is the coach playing for the one season to close out the regular season. The Niners have gone from under a three percent chance to earn a bye to a coin flip.

Shanahan will have to do it against one of the best defensive minds and defensive lines in the NFL. The Seattle Seahawks have also won six consecutive games. Mike Macdonald is tied for the most wins in the NFL in just his second season as a head coach. He’s quickly ascended into one of the more impressive coaches there are in this league, presenting a unique challenge for the 49ers in Week 18.

For much of the season, the 49ers have been involved in higher-scoring games. The Niners’ offense has been able to dictate the pace, get out ahead of their opponent, and cruise to a victory.

Stringing together multiple first downs against this Seahawks defense has been a struggle for most teams they’ve faced, let alone touchdown drives. The Rams were the only team to make Seattle look league average, but they score against everybody. Then again, so do the 49ers.

Saturday night, for the No. 1 seed, it’ll be best on best on one side of the ball, and a pair of units limping to the finish line on the other. Let’s start with the side of the ball that’ll determine the matchup.

49ers passing attack versus the Seahawks’ passing defense

A battle of the bigs

We didn’t think there was a reason to mention the 49ers’ offensive line against Chicago’s defensive line last week, as they hadn’t shown the ability to get after the quarterback. Sure enough, Brock Purdy was pressured on only 23.7 percent of plays, the offensive line allowed more than a yard before contact, and the unit continued to roll despite not having Trent Williams.

The 49ers’ offensive line has been gelling for a month now. For the first few games of the season, they didn’t know who to block in the running game. Now, they are as synchronized as they’ve been all year. The play below is a prime example:

We’d be doing you a disservice to ignore the trenches this week, so let’s start there.

Interior pressure is king in the NFL. The Bears’ top defensive tackles have combined for 53 pressures this year. Byron Murphy and Lenoard Williams have 44 pressures each. They have combined for the most of any defensive tackle duo, and are the only interior combo to rank in the top 10 in pressures at their position in two seasons.

49ers center Jake Brendel has been lights out for much of the season. It’s a sentence that many fans are still reluctant to accept. According to Sports Info Solutions, Brendel has had only four games with two or more blown blocks all season. He’s had four games without missing a block. SIS rates Brendel as the 11th-best center in the NFL, and Dominick Puni as the third-best right guard. Puni had a rough game against the Titans in Week 15, but since Week 8, that was the only blemish along the way. He’s been excellent.

The concern in this game is left guard Spencer Burford. Despite this being Burford’s fourth season, he’s effectively a rookie at left guard. And he’s only been playing full-time for a few games now. It shows. There are a handful of plays in a game that make you wonder what took so long for Burford to kick inside. There are five other plays in which it looks like a player is in over his head. How Burford holds up will likely determine how aggressive Kyle Shanahan can be as a play-caller.

The Colts had the most diverse pass rush the 49ers faced, with five players having over 20 pressures. But they caught DeForest Buckner fresh off the Injured Reserve, and only one player had over 40 pressures. Seattle is a different animal. They have six players with at least 37 pressures. We mentioned Williams and Murphy inside. DeMarcus Lawrence, Uchenna Nwosu, and Boye Mafe are all a presence disruptive enough to force you to leave their interior rushers 1-on-1, which is how you end up with a dominant defensive line that constantly gets after the quarterback.

Let’s act as if Trent Williams won’t play on a short week. Austen Pleasants will make his first start of the season. This time, he’ll go from going against pass rush first players, like Austin Booker of the Bears, to a completely different style of physicality and player, like Demarcus Lawrence.

Niners offensive line coach Chris Foerster said Pleasants’ Week 17 performance was “hovering just above the line,” adding that “It wasn’t quite what we wanted, but it was good enough.”

Foerster, 64, has been coaching football since 1983. He’s seen this situation time and time again. So when Foerster says, “It’s funny. You throw a guy into the middle of a game, and he plays OK sometimes. But then he has a whole week to think about it, a whole week to prepare, a whole week to study tape, and he’s not as good,” you can’t ignore it.

Does that mean the 49ers will have to go from sliding their line one direction to help right tackle Colton McKivitz out, to sliding it the opposite way, and now McKivitz is a player on the island?

Statistically, McKivitz has been phenomenal this year. Sports Info Solutions rates him as the fourth-best right tackle, having missed only four blocks against the run. McKivitz has drastically improved in pass protection, but he still has that one play a game that makes you worry.

The 49ers’ offensive line has evolved into a strength, but Seattle is one of two teams (Houston) that can out-physical them up front and control the line of scrimmage. This puts more pressure on the skill players, which isn’t necessarily a bad thing for one of the best passing games in the NFL.

Going down swinging with your stars

In a playoff setting, against your rival, you’re not going down swinging with Demarcus Robinson. Jauan Jennings will be factored in, but this is a George Kittle, Christian McCaffrey, and Ricky Pearsall game.

Week 1 feels like ten years ago. Kittle played 21 of the 76 snaps to open the season. He caught all four of his targets for three first downs and a touchdown. Pearsall caught four of his six targets for 108 yards, with all four of those resulting in first downs. McCaffrey was the workhorse, catching nine passes on 10 targets, gaining 59 yards after the catch, picking up three first downs, and forcing four missed tackles along the way.

Macdonald’s defense is a nightmare matchup for 95 percent of offenses. Thanks to cornerbacks Devon Witherspoon and Tariq Woolen, you don’t beat them outside of the numbers. Citing DVOA, which adjusts for opponent, the Seahawks are second against the pass overall, second in limiting the No. 1 receiver, and fifth at taking away your No. 2 receiver.

Paired with the pass rush, it’s a scheme that works. Most teams are still living in the NFL of yesteryear and not attacking the middle of the field. The Rams and 49ers do.

Two weeks ago, the Rams had gains of 58, 54, and 41 against Seattle’s linebackers and safeties. They schemed up another 27 and 19-yard gain with an eligible matched up against an edge rusher. Rookie safety Nick Emmanwori is an athletic specimen, but he’s still a first-year safety, and it shows in coverage. Sean McVay targeted him five times, and Emmanwori gave up five receptions for 44 yards and four first downs.

On the year, the Seahawks are 14th in DVOA at defending slot receivers and 19th at taking away tight ends. They actually allow the second-most yardage to tight ends at 70.8 per game. Could Week 1 hero Jake Tonges see the field at the same time with Kittle? The matchup calls for it.

We can expect to see Pearsall in the slot– or at least motioned to the slot at the snap. That’s where he’s been most effective as of late. These are teams that live in condensed formations. The 49ers’ offense has used condensed formations — a total width of 20 yards — at the highest rates in the league. The 49ers are at 65 percent on the year, but have upped that number to 77.1 percent since the bye week. It’s worked, as they have the third-best EPA per play in those condensed formations during that span.

Those formations should help slow down a defense that has generated the fourth-highest pressure rate in the NFL, despite hardly blitzing. As impressive as Seattle’s pass rush has been this season, five players are in the top 32 in pressure rate, they don’t sack the quarterback. The Seahawks are 26th in sacks per game.

Pressuring Bryce Young, Matthew Stafford, Philip Rivers, Kirk Cousins, and Max Brosmer is one thing. Purdy is one of the few quarterbacks in the NFL who seems to thrive under pressure. The more chaotic the play, the calmer Purdy remains. He may run around in the backfield for 6+ seconds, but the result has been kind to the 49ers.

Purdy has completed 11 of 15 passes for 132 yards and four touchdowns since the 49ers’ bye week on throws outside of the pocket. On the season, he has the third-highest passer rating on throws outside of the pocket. Purdy leads the league in passer rating since the bye by nearly 20 points on throws longer than 2.5 seconds. He had nine touchdowns to zero interceptions. Since returning from injury, only Justin Herbert has thrown for more yards on plays that have lasted over four seconds than Purdy.

It’s unlikely this will be a game where Purdy can scramble to run, as Seattle has allowed the 10th-fewest scramble yards on the year, but they’ve allowed the fifth-most passing yards to quarterbacks scrambling, playing right into Purdy’s hands.

Furthermore, we know Purdy is not the kind of quarterback who scrambles for short passes. Kyle Shanahan joked with Purdy during a mic’d-up segment against the Colts, where he said, “I’m proud of you.” It was said in sarcasm as Brock took the checkdown.

Purdy is completing 60 percent of his passes on throws beyond ten yards, second-best in the NFL. Since the bye week, Purdy has the highest passer rating and is second in passing yards on throws beyond 10 yards. It’s who he is, a big play hunter.

Identifying the mark: Nick Emmanwori is a player the Seahawks identified as a scheme fit because of what he can do near the line of scrimmage. However, he didn’t look comfortable in coverage in college, and that’s been the case this season. We mentioned the Rams’ success when throwing Emmanwori’s way. I think it’s telling how often quality teams or division opponents isolate Emmanwori in coverage. The Jags targeted him eight times. The Texans seven. Arizona 11. Kevin O’Connell seven.

If the 49ers get into a manageable passing situation, I’d expect Shanahan to target the rookie who has surrendered a first down on 45 percent of his targets.

Player to know: Safety Coby Bryant is doubtful for this game. That means Ty Okada, an undrafted free agent out of Montana State, will start at safety. He’s played 697 snaps this season, but what I’ve noticed is that with Okada on the field, Macdonald has trended more conservatively in coverage, often leaving two deep safeties and allowing passing yards underneath. That’s good news for McCaffrey.

There will be about five to six plays in this game where the 49ers can be matched up downfield against Okada 1-on-1. It’s the same route, a “7-cut” or a corner route. Think what the Bears did last week on 3rd & 14 to the 49ers. On the year, Okada has allowed receptions of 24, 20, 23, 26, 41, and a few other double-digit gains. It’s one of the 49ers’ must take advantage of, as those chances will be few and far between.

Seattle has the 4th-highest cloud coverage (where at least one quarterback stays short to defend the underneath area) in the league. Brock Purdy is averaging the fifth-highest yards per attempt when facing cloud coverage. The opportunities to make plays will be there, especially if Shanahan schemes something up in a timely fashion.

Advantage: If the 49ers were an offense that attacked outside of the numbers, it’d be a terrible matchup. They are not, which is why I believe the 49ers have the advantage through the air.

49ers rushing attack versus the Seahawks’ run defense

The 49ers’ scoring spree has come on the backs of their best rushing performances of the season. The Week 1 rushing total remains the biggest surprise, given that Seattle has turned into the second-best rushing DVOA defense since Shanahan became a head coach.

Seattle has allowed the lowest EPA per rush by a healthy margin, has allowed the second-fewest 10+ yard carries, and is inside the top seven in both stuff rate and yards before contact allowed.

Everything said above about Emmanwori in the pass is the opposite against the run. He’s a demon. Despite missing four games early in the season, Emmanwori is ninth among all safeties in run stops. He’s fast, physical, and plays at a speed with an aggression that few receivers or tight ends are used to — hence, his 12 tackles for loss.

The Seahawks are the best team in the NFL in third-down efficiency because they stop the run. They’re a buttoned-up unit that doesn’t make mistakes. Seattle allows the lowest rate of any team in the NFL for 10+ yards on designed runs. At 5.3 percent, that’s the second-lowest of any team since 2016. They also tackle extraordinarily well. They’re missing tackles against the run at the second-lowest rate, and the 2.2 yards they allow when making contact behind the line of scrimmage is the fewest of any defense since 2020.

The running game is where the 49ers will miss Trent Williams the most. McCaffrey has forced a league-high 112 missed tackles this season. He’ll need to do more of that on Saturday night.

Player to know: Byron Murphy has an argument that he’s the best defensive tackle against the run in the NFL. His teammate Leonard Williams has 39 stops, good for second in the league. Murphy has 36. It’s impossible to simulate the force he plays with. After seeing the success Jeffery Simmons had a few weeks ago, it’s difficult to imagine Murphy not doing something similar and single-handedly forcing Shanahan to forgo the running game.

Advantage: As well as the Niners have run the ball during the previous three weeks, they are running into a historic rushing defense that can push them around a bit, create negative plays, and overwhelm them 1-on-1. The Seahawks have the advantage here.

What to make of the Seahawks offense and Sam Darnold in a big spot

For much of the second half of the season, I’ve been convinced the Seahawks were the best team in the NFC. Most teams can’t do what the Rams did to them through the air in Week 16, and theoretically, what the 49ers can do to them in Week 18. Most teams looked like Carolina last week.

Football is fluid. We get new information each week. The inconsistencies from the Seahawks’ offense since Week 11 are alarming.

When I watch them, I see an offensive coordinator who does not know what to do, nor can he find a rhythm. I see a quarterback who isn’t sharp, nor does he trust what he sees. I see a pair of running backs that leave yards on the field and leave plenty to be desired, despite the occasional big play. I see an offensive line that looks lost without left tackle Charles Cross, who is ruled out for this game. His backup, Josh Jones, has an ankle and knee injury and is listed as questionable, despite not practicing all week.

Seattle has excelled on a down-to-down basis since Week 11, ranking 10th in success rate. However, they’re 21st in EPA per play, 26th in dropback EPA, and 19th in rushing success rate.

On the season, Sam Darnold is getting sacked the eighth-most per game, throwing the seventh-most interceptions per game, and leading an offense that fumbles the fifth-most per game. It’s hard to be efficient in situational play when that’s the case, so it’s no surprise to see Seattle 15th in third-down efficiency and 18th in red-zone efficiency. The 49ers’ defense is 15th on third downs and in the red zone.

Will Robert Saleh have the confidence to play Luke Gifford again against the Seahawks ‘ two-tight-end sets? Seattle’s at their best when they are in 12 personnel, averaging 7.7 yards per play, the highest of any offense since 2018. Their heavy groupings aren’t limited to 12 personnel. Seattle has used two or more tight ends and running backs on 57.4 percent of their plays this season, leading the league with 6.0 yards per play in those situations.

Gifford played 15 snaps last week against a team that does something similar. He played the run well, but allowed a 32-yard reception. Will the Big Nickel snaps with Jason Pinnock continue? Pinnock had a stop last week, but also allowed a 24-yarder in coverage. Neither option seems appealing.

This season, the 49ers have used nickel on 66.3 percent of their snaps against 12 personnel, which is the 4th-highest mark in the league. I would have a difficult time taking Upton Stout off the field, assuming he clears the concussion protocol. But this specific matchup is why you go out and sign Gifford.

Saleh reverted to many vanilla looks against the Bears. San Francisco had the fifth-highest stunt rate in Week 17, but had the fourth-lowest blitz rate and seventh-lowest simulated pressure rate. However, Sam Darnold is a quarterback that you want to heat and speed up.

Darnold, like Purdy, thrives on throws outside of the numbers. Darnold has the highest passer rating this season on throws outside of the numbers. But he’s turned the ball over at the highest rate in the NFL when he’s been pressured.

Seattle goes out of their way to protect Darnold by running the ball a ton, but, eventually, you have to play quarterback in this league. Darnold, despite being pressured at the fifth-lowest rate this season, has thrown six interceptions under pressure, lost five fumbles on strip sacks, and lost 255.5 percentage points of win probability when pressured, which is the second-most in the NFL behind Jalen Hurts.

A week after putting up a donut, can Bryce Huff take advantage of a backup left tackle? He has more than twice as many pressures and quick pressures as any other 49ers pass rusher. It’s a game where the 49ers need Huff to show up and create chaos.

There’s no secret where Darnold wants to go with the football. Jaxon Smith-Njigba accounted for 91 percent of the Seahawks air yards in Week 1. Why would that be any different this time around? Deommodore Lenoir publicly stated he wants to travel with Smith-Njigba. Be careful what you wish for. He’s a game-changer. With JSN on the field, Seattle averages 6.6 yards per play. When he’s not on the field, that dips to 3.6 yards per play, which is the largest split in the NFL among all wide receivers.

Like Pearsall, Smith-Njigba is targeted predominantly down the field. Saleh loves Cover 4. He’s dialed it back in recent weeks, falling back on more of a Cover 3 style. On the season, Smith-Njigba has a league-high 33 receptions for 546 yards against Cover 4, which is nearly twice as many as the player in second place. Smith-Njigba is being targeted 44.6 of the time against quarters coverage.

Surprisingly, the 49ers have fared well against the opposition’s top threat this season, ranking 10th in DVOA. But this isn’t your typical No. 1 wideout. Smith-Njigba beats every coverage. On 28 targets against man coverage this year, he has 23 receptions, 19 for first downs, and has caught seven of nine contested targets. We are talking about a top-three receiver. You know you’re special when everybody knows you’re getting the ball, and they still cannot stop you.

More recently, Cover 3 and Cover 1 have been Saleh’s changeups. Last week, against an elite offense, the 49ers ran Cover 3 at the 10th-highest rate and Cover 1 20.2 percent of the time. With Renardo Green back, Saturday night might be a situation where you get an extra set of eyes on Smith-Njigba with a safety, and make the Seahawks consistently win with somebody else.

The offense looks off, no matter how you slice it. That bodes well for a 49ers defense that has made the most pedestrian offenses look good. Zach Charbonnett and Kenneth Walker do well at forcing missed tackles and gaining yards after contact, which is a concern against a defense that has been sloppy in that department this year. However, they only missed seven tackles against the Bears. It’s a different defense with Tatum Bethune on the field, especially against the run.

The Seahawks defense is indeed a massive step up in class for the 49ers offense. It’s also accurate that going from the Bears offense to the Seahawks offense is one of the bigger step-downs you can have going from one week to another.

Seattle didn’t score a touchdown at home against the Colts. Last week, against the Panthers, Seattle’s first six drives went like this:

Punt
Field goal
Punt
Fumble
Turnover on downs
Interception

Carolina fumbled on the first play, gifting Seattle the ball at the 21-yard line before they scored a touchdown. An interception on the ensuing drive gave the Seahawks the ball at the 29-yard line. Their third touchdown drive was 25 yards after another turnover on downs. The 27-10 score is a mirage of what transpired during the game.

The score will resemble what we saw in Week 1, or at least much closer, compared to what we saw in Week 17 from the 49ers. That’s a good sign for the home team, as you can’t hold them down offensively forever. There’s not enough evidence to suggest the Seahawks will “get right” in this spot.

Improbably, nearly two months after being embarrassed at home by the Rams after allowing six touchdowns, Shanahan and Saleh close out the best coaching jobs of their careers with a win, propelling the 49ers to the No. 1 seed.

49ers 23, Seahawks 20.