Seahawks vs. 49ers: 3 things to know ahead of critical Thursday matchup

“This is gonna hurt.”

“This is gonna hurt.”

“Promises, promises.”

They don’t have to enjoy it like Nebula, but Seahawks fans should probably prepare themselves for a bit of pain and domination this evening. Winners of six straight, the NFC West super-rival 49ers are in town tonight with a chance to clinch the division and put Seattle’s postseason ambitions on the ropes.

Even with a serious question mark going on at QB, the Niners are a far superior football team right now. After all, they have the league’s top scoring defense this season and they held Seattle’s offense scoreless the last time they met. It doesn’t help that this Seahawks team is struggling in a bad way coming into Week 15.

Here are three things to know before tonight’s matchup.

Biggest key for 49ers defense in Brock Purdy’s 1st start

Brock Purdy’s No. 1 goal has to be avoiding turnovers. The good news if he does commit one — his defense is the extra stingy after a giveaway.

Much of the optimism about the 49ers despite third-string quarterback Brock Purdy, a rookie selected with the final pick in the draft, exists because of his supporting cast on offense and the 49ers’ terrific defense.

The stats anointing San Francisco’s defense as the NFL’s best are plentiful, and the fact they’re holding opponents to just 15.8 points per game will be helpful in limiting the onus on Purdy to make plays in his first NFL start.

While Purdy put together a strong debut in relief of Jimmy Garoppolo a week ago, it stands to reason that his first start will come with a handful of rookie mistakes. He’ll be facing the Buccaneers and head coach Todd Bowles who’s helped lead Tampa Bay’s defense to No. 5 in scoring and No. 8 in yards allowed through 13 weeks.

Even though Tampa Bay ranks 30th in the NFL in takeaways, it’d be understandable if Purdy’s first start came with a couple of turnovers. That’s another way his defense will act as a safety net against some of the inevitable hiccups of a first-time starting QB. It’s the same reason the club was willing to start Trey Lance and let him work through some ups and downs while they continued contending for a Super Bowl.

This season San Francisco has allowed only nine points off turnovers. That’s the lowest mark in the NFL, and they’ve given the ball away 14 times.

Last week Purdy’s one interception – what amounted to an arm punt on a fourth-down jump ball for Brandon Aiyuk – resulted in a Dolphins punt after just four plays.

Ultimately success for Purdy will come down to converting third downs and not committing turnovers. For the times he does give it away either Sunday or at any other point down the stretch though, his defense will more than likely keep it from turning into a disaster.

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How the 49ers’ dominant defense works from front to back

The San Francisco 49ers’ defense has been amazing over the last month. Laurie Fitzpatrick details how it all works from front to back.

The San Franscico 49ers have morphed into one of the most dominating defenses in the league, especially in the trenches.  Over the last three weeks they have allowed zero second half points and have also allowed the second least amount of yards per play, 4.5, per teamrankings.

Joey Bosa, Fred Warner, Dre Greenlaw and Talanoa Hufanga are the heart of this defense. They have been playing like an absolute unit and they are all lead by second year defensive coordinator DeMeco Ryans.

Ryans’ prides his defense in getting to the ball quickly. He was asked about tackling after last Sunday’s 13-0 win over the New Orleans Saints, here is what he had to say: “We want all eleven guys, as fast as they can, shooting their gun, it doesn’t matter if you miss a tackle, there should be two or three guys there to clean up. That’s just our mentality, a swarm mentality. tracking inside heel, being in proper leverage, and when you get there, there is no hesitating”.

The 49ers defense registered only one missed tackle against the Los Angeles Chargers per Pro Football Focus, and they had a similar performance in week 11 against the Arizona Cardinals.

Let’s dive into the film to diagnose the swarm mentality they have in all three levels of the defense!

How San Francisco 49ers DC DeMeco Ryans created the NFL’s best defense

San Francisco 49ers defensive coordinator DeMeco Ryans has built the NFL’s best defense. Here’s how that happened.

The San Francisco 49ers have done all kinds of remarkable things on defense this season, but this Deommodore Lenoir sack of Matthew Stafford with 45 seconds left in the 49ers’ 24-9 Monday night thrashing of the defending Super Bowl champion Los Angeles Rams really stood out.

The Rams had third-and-13 from their own 30-yard line, and San Francisco defensive coordinator DeMeco Ryans was dialing up some STUFF. Pre-snap, safeties Tashaun Gipson and Talanoa Hufanga flipped deep coverage, with Gipson coming down from single-high, and Hufanga replacing him. That put Gipson in the right slot, but post-snap, when you think he’d cover Cooper Kupp upfield, Gipson instead carried Kupp to linebacker Fred Warner, who somehow (I don’t know how) matched Kupp 25 yards through the seam over the middle. Warner had come from a blitz look to do so. So, Gipson was now free to come back down and cover the flat, eliminating Stafford’s hot route to tight end Tyler Higbee.

There was a blitz, but it wasn’t the one Stafford likely expected. Lenoir, who looked to be in press position on Kupp, flew right by the receiver to the quarterback, making up for the fact that Warner and fellow linebacker Dre Greenlaw had dropped into coverage. Higbee gave Lenoir a “good job, good effort” chip on the way to his route, but that wasn’t enough. At all.

Meanwhile, cornerbacks Emmanuel Moseley and Charvarius Ward had their receivers Ben Skowronek and Allen Robinson, respectively) covered tight all the way up in a twisted version of Cover-3. Had Lenoir not gotten to Stafford first, edge-rusher Nick Bosa was on his way there, terrorizing the Rams’ offensive line with a multi-gap stunt — Bosa started head-up over Higbee, and finished the play wrestling with left guard Bobby Evans.

After watching this 4-D zone exchange, I came to one simple conclusion:

The amount of coordination that goes into these plays — the tying of specific skill sets to scheme — has worked so well for Ryans’ defense. And that’s as much about coaching as it is about execution.

The 49ers currently rank first in Football Outsiders’ Defensive DVOA metric — fourth against the pass, first against the run. They’ve done it with established stars like Bosa and Warner and Greenlaw, but they’ve also done it with under-the-radar defenders like Gipson (who hasn’t allowed a single catch on four targets this season), Hufanga (who’s playing like an embryonic Troy Polamalu these days), edge-rushers Samson Ebukam and Charles Omenihu (who have 14 and 13 total pressures in the young season, respectively), and Ward (who’s excelled as the 49ers’ most-targeted defensive back).

Head coach Kyle Shanahan knows exactly who’s responsible for his top-tier defense, as his offense struggles to transcend Jimmy Garoppolo’s ceiling.

“DeMeco is so naturally talented and he’s good at everything he’s ever done and he really understands football,” Shanahan said of his defensive coordinator the day after the Rams game. “He did as a player, he did as a quality control in his first year. He did as a linebacker coach and he has as a coordinator and he was good right away. But anytime you have someone who does have those type abilities, the more reps they get, like everybody, they get better.

“You go through experiences and you learn from the good and the bad and that’s what’s pretty neat about DeMeco because he was going to be good regardless, but just watching him throughout last year, each game, each quarter he learned something. And he’s always trying to think and always trying to challenge his players, but always trying to keep it simple, too. And it’s where it at least seems simple and that’s why he gets better every game that he goes.”

The SEC Defensive Player of the Year for Alabama in 2005. A linebacker for the Houston Texans and Philadelphia Eagles from 2006-2015. The AP Defensive Rookie of the Year. A two-time Pro Bowler, and then, a defensive quality control coach and linebackers coach for the 49ers before he became defensive coordinator in 2021. Ryans has succeeded over and over in football, he’s gotten better at his current job as Shanahan said, and his defense obviously reflects that.

But what is DeMeco Ryans doing that has the rest of the NFL in an absolute tizzy?

Film study: Why Fred Warner is crucial to Niners defense

Touchdown Wire’s Laurie Fitzpatrick breaks down film to explain why 49ers linebacker Fred Warner is so valuable.

The San Francisco 49ers improbably have earned a spot in the NFC Championship Game.

The sixth-seeded Niners were road underdogs against the Dallas Cowboys and Green Bay Packers. Undeterred, San Francisco won those games by six and three points, respectively.

Now, the Niners meet a familiar foe in the NFC West-rival Los Angeles Rams with a trip to Super Bowl LVI at stake.

San Francisco’s defense is playing at a high level, having only allowed three touchdowns in those two games. Aaron Rodgers and the Packers only reached the end zone once last week, and when we dove into the film, we saw why. The secret to the 49ers’ defensive scheme went through middle linebacker Fred Warner.

Last week, Warner and defensive end Nick Bosa were graded as the top defenders of the game by Pro Football Focus.

As PFF’s Seth Galina pointed out, for the entire game, the Niners’ defensive tackles lined up in 2i technique (off the center) forcing the double-team and freeing up the A gap for Warner to penetrate.

Most zone-blocking schemes use double-teams when running the ball up the middle, as the linemen work up to the second level of the defense.

The great thing about zone blocking is that if the running back has good vision and patience, the ground game can be extremely efficient. The downside is if you are playing a team with flexible defensive tackles, the defense can essentially open the lanes that it chooses depending on where its players line up. Once a gap is opened up from a double-team, the offensive linemen won’t have time to work their way up to the second level with a linebacker coming through the middle — as seen in the clip above.

Back in Week 18, the Rams offense ran similar plays. In the clip below, they clog the middle with blockers. But Warner switches to the B gap and makes the tackle, anyway.

One of the main differences between the first clip and the second was how motion shifted the linebackers, leaving the A gap devoid of defenders. If ball carrier Sony Michel would have cut to the outside, he may have had success against nickel cornerback Dontae Johnson as left guard David Edwards was working his way upfield.

A few weeks later, Warner no longer shifts, giving the offense no open lanes for the tailback.

Below is an example of Warner and weak-side linebacker Dre Greenlaw moving together on a string to keep the gaps plugged.

Over the course of the season, many of the Rams’ most successful run plays went to the outside. So the Rams might try to get between the ends and tackles (C gap) along the 49ers’ wide-nine defensive line.

Last week, Warner received the highest PFF grade of his career, 94.2. This grade was deserved not only because he dominated in stopping the run. He used the same aggressiveness and anticipation in the screen game as well.

In the clip below, Warner’s responsibility in coverage was to pick up tailback Aaron Jones escaping into the flat. But as soon as he notices the offensive linemen getting upfield, he no longer waits to be blocked. Instead, he engages Jones as the ball arrives from Rodgers.

We saw how Warner can be a force up the middle against the run and his aggressiveness when identifying a screen pass. Now let’s move on to the downfield passing game, where Warner’s coverage flexibility really is something special.

One of the best receivers in football right now, Cooper Kupp, is someone Warner will have to monitor when dropping back into zone coverage against the Rams — because the Niners can’t afford to give up big plays downfield.

On Sunday, expect to see Warner drop back into coverage with his eyes on Kupp. This will give the Niners’ defensive line time to apply pressure and try to force Stafford into bad throws. This is what led to an interception by the Niners defense in Week 18.

Similar to the clip above, last week against the Packers, Warner was aware of Green Bay’s No. 1 receiver, Davante Adams, who was running a crosser over the middle of the field.

Warner stays in the line of vision between Adams and his quarterback, forcing Rodgers to dump the ball off to tight end Marcedes Lewis. Warner then forced Lewis to fumble, and Greenlaw recovered. Turnovers such as these can change the complexion of a game.

Not only does Warner have good acceleration, but he also can drop into a deep quarter or third when asked.

Warner’s fluid hips and speed allow him to keep up with just about any tight end in the league. During this postseason, Warner ranks second overall among linebackers in pass coverage, with an 88.5 PFF grade when dropping back in man defense.

If the Rams come out in an empty set, expect Warner to cover tight end Tyler Higbee as he goes deep. This will be a key man-coverage matchup to look for. When Warner drops into zone coverage, he will be looking to help bracket Kupp as he runs across the middle of the field. (Bracketing is when one defender is high, above the receiver, and another defender is low, in front).

If the Niners are to beat the Rams on Sunday, the San Francisco defense must play a big role — and the Rams would be wise to account for Warner in both the passing and run game.

49ers defense has been excellent at getting off the field

The #49ers defense has been excellent at getting off the field in 2021.

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While the 49ers’ offensive struggles have garnered the spotlight, their defense is quietly overcoming some adversity to put together a really nice season. Two numbers in particular jump out as important figures for them when it comes to sustaining a unit capable of making the postseason.

While San Francisco’s defense is No. 7 in yards allowed, No. 15 in points and No. 12 in defensive DVOA (Football Outsiders’ defensive efficiency metric), they sit near the top of the NFL in third-down conversion rate and fourth-down conversion rate. They’ve done an excellent job getting off the field on those key downs.

The 49ers going into Week 7 are No. 4 in third-down conversion rate and No. 2 on fourth downs. Those would normally be the kind of numbers that spearhead one of the NFL’s best teams, but their offensive struggles have put too much of the onus on the defense to play at a high level for too many possessions.

If San Francisco’s offense can get out of the rut its been in since Week 2, they’ll provide enough support to make the defense’s third and fourth-down dominance a key part of their bounce back into the thick of the playoff picture.

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