How Steve Spagnuolo got unblocked pressure at Brock Purdy

One of the keys to the Chiefs winning the Super Bowl was the pressure the defense had on the 49ers’ quarterback.

On Sunday, Kansas City Chiefs’ defensive coordinator drew up another impressive gameplan against a Death Star of an offense from the San Francisco 49ers. After starting in a safe, conservative defensive shell early, Spagnuolo quickly adjusted following some issues.

He got way more aggressive with his fronts, pressures, and playing more man coverage. This helped limit the 49ers running angles and attacked the biggest weakness of the 49ers — their suspect protection schemes.

No stat embodies this more than that the Chiefs had nine unblocked pressures on quarterback Brock Purdy, all of which came on blitzes. The Chiefs’ defensive line struggled to generate pressure on their own, so Spagnuolo failed more blitzes to get consistent pressure, which changed how the 49ers called plays and took them out of a rhythm.

Let’s break down some of the pressures that Spagnuolo used;

It seemed like Shanahan was focused on making sure Chiefs linebacker Leo Chenal wasn’t blowing up the 49ers’ plays with his blitzing ability, so Shanahan did a lot to try and mitigate that. He worked to get his running backs isolated with Chenal in coverage but also frequently slid protections to his side to account for him as a blitzer.

Spagnuolo took advantage of this frequently, getting free runners on the backside to take advantage of Chenal’s gravity. The Chiefs initially put Chenal on the edge, mugging the line of scrimmage. The 49ers responded by full-sliding the entire offensive line to that side, accounting for the fact that Chenal could slide into any gap on some sort of stunt. This allows Nick Bolton to be free on the backside C-gap. Purdy accounts for this well by getting to his hot, but cornerback L’Jarius Sneed gets a two-hand jam on Deebo Samuel to destroy the timing of this hot route.

This play was an example of good process and bad results. The Chiefs get two free runners vs. a five-man protection. Drue Tranquill gets to come free based on the way the protection slides, but Bolton should never get unblocked as well. The reason he was is that defensive end George Karlaftis does an excellent job slanting and squeezing inside one gap, which gets the right tackle to put his eyes inside and not push out to Bolton. The slide gets congested, so the right guard can’t peel off and get to Bolton running free. The 49ers get a touchdown off of this, but good work by Karlaftis to take advantage of the right tackle’s eyes and let Bolton get free on this rush.

After a rough start from their ordinary even 4-3 fronts, Spagnuolo adjusted to playing more 6-1 fronts. When the Chiefs would be in nickel personnel, they would put both linebackers on the ends of the line of scrimmage and put safety Justin Reid as the long off-ball linebacker. You play this defense because it limits the way the 49ers get to their wide zone runs – their main under-center run – by not allowing double teams to the second level.

This also helps you deal with bootlegs since you have a backside runner at the quarterback. That happens in this play, where the 49ers offensive line moves completely to the left, leaving Bolton on the backside. By putting Bolton on the edge, he’s got a better angle to the quarterback and limits the ability to throw from there.

The Chiefs completely took the 49ers rollout game off the menu by adjusting their fronts. It required them to concede they would always be in single-high coverages (typically man coverage), but since the Chiefs are so strong at defensive back, they’re okay with that. Spagnuolo preferred to take away those wide zone runs and the bootlegs instead, and they were successful in that.

The biggest defensive play of the game, in my opinion, was this third-down stop. If the 49ers convert this play, they could’ve burned all of the Chiefs’ timeouts and given them the ball back with 1:10 in a best-case scenario. It was up to Spagnuolo to make his best call in a critical situation to give the Chiefs a chance.

So, Spagnuolo comes out in dollar personnel – two defensive linemen, two linebackers, and seven defensive backs. He is daring Shanahan to call a run play, but Shanahan doesn’t oblige. He puts tight end George Kittle in the backfield, which gives away this is a pass. Up front, he has Willie Gay over the center and Bolton in the B-gap. After the snap, the 49ers send a four-man slide to Bolton on the backside, taking care of any slanting frontside. The left guard is occupied by Bolton’s blitz, allowing McDuffie to blitz freely through the B-gap.

Spagnuolo did a terrific job of using his linebackers to dictate protections. He had a beat on what the 49ers were trying to do with their protections and utilized his linebackers as his way to unlock other blitzes from the secondary. In Spagnuolo’s most significant moments, he turned to his best blitz call to get the stop.

On the last defensive play of the game, Chris Jones gets a free run at Purdy through the B-gap. How did the 49ers leave the Chiefs’ best pass rusher unblocked? Well, mainly, the 49ers call a weird protection. They try to pull the center around, something they had done multiple times in the game. The Chiefs are in a 5-0 look presnap, putting Bolton in the A-gap. Likely, the 49ers should’ve canned the protection and kept the center inside, but the 49ers didn’t adjust the protection.

Since they want to pull the center around, the right guard has to squeeze down to take Bolton. The right tackle should likely squeeze down as well, but there is some miscommunication with the right tackle and guard.

I’m not sure why Shanahan called this protection against a team that calls as many Cover 0 blitzes as Spagnuolo did, but he still deserves credit for making the 49ers bust their protections as often as they did. This 5-0 look seemed to confuse the 49ers all night, so kudos to Spagnuolo for noticing that and taking advantage of it.

The bottom line

The most important decision the Chiefs made this past decade was drafting Patrick Mahomes. Nothing will ever change that. But there’s a real case that hiring Spagnuolo as defensive coordinator is the second-most important decision the Chiefs made.

Spagnuolo was a considerable risk. His last stop with the Giants wasn’t overly productive, and he had real failures in the NFL. He wasn’t guaranteed to succeed, but he’s been nothing but that for the Chiefs for years. Slowly yet surely, they’ve added pieces to the defense that allow Spagnuolo to add more to his bag. Combine that with great personnel decisions from the front office, and the way this Chiefs defense has been assembled is one of the more impressive front office jobs I’ve seen.

This season wasn’t about Mahomes or the offense. They did enough to win a Super Bowl, but the true story of this season is Spagnuolo and the defense. He has a real case to be the best defensive coordinator ever and a Hall of Famer. If you would’ve told me that in 2019, I would’ve called you crazy, but it’s completely justified at this point.