49ers film room: What is a quarterback pressure? Part 1 - Using examples from the Super Bowl and preseason to show the differences
Today we look at a common trope that the 49ers offensive line allowed 9 unblocked pressures in the Super Bowl, what a quarterback pressure is/isn't, and we'll look examples from the preseason later.
A common trope among 49ers fans is that the offensive line is generally poor or below average. To prove this out, fans and 49ers beat writers often cite nebulous concepts like “pass block win rate,” “pressure to sack rate,” and “total pressures” from various charting agencies to show that Brock Purdy is under duress often. If he’s under pressure often, then it must mean all the pressure given up is the responsibility of the five blockers in front of him
.This is hardly true. But one stat that kept making the rounds this offseason is that the 49ers faced nine unblocked pressures in the Super Bowl versus Kansas City. NINE! That seems bad, with fans and local beat reporters often attributing this to bad game-planning by Kyle Shanahan and bad offensive line play with claims like “imagine if Brock had an offensive line” followed by critiques of the offensive line, the coaching decisions to draft certain players, etc. You can read the quote tweets on this and find dozens of comments attributing this to the offensive line.
First, a general comment on the nine unblocked pressures in the Super Bowl. Chiefs defensive coordinator Steve Spanuolo deserves a ton of credit for this game plan but it’s hardly the first time this offense with Shanahan has faced unblocked rushers that negatively affect plays. It just happened to be against a top 3 defense in the Super Bowl. Spags deserves 100% of the credit here for a great game plan.
But the unblocked defender issue the 49ers offense experiences has gotten progressively worse the last two seasons in that it’s hard for Brock Purdy to identify the blitz because opposing defenses know not to show their hand pre-snap because they know Brock isn’t setting the protections or changing them just before the snap. This is a bug in the Shanahan tree offenses. It’s off-shoots with Sean McVay and Matt LaFleur give the quarterback that responsibility.
Nine unblocked pressures in the Super Bowl
When fans and local writers cited the nine unblocked pressures in the Super Bowl, it came with a lot of missing context. The stat included the infamous 3rd-and-4 in overtime when right guard Spencer Burford went the wrong way. It also included a similar play where left guard Aaron Banks went the wrong way on the same, but flipped, play action pass protection earlier in the game.
Now, the overtime play is a big deal because it cost them the game in that moment for sure (among other reasons I already wrote about). But by my own charting, 7 of those 9 pressures were not the responsibility of the offensive line at all.
Since Brock Purdy does not have the freedom to change the protection pre-snap and must rely on the center’s call, this means he must quickly see and identify the rush in the post snap. This puts a ton of pressure on him to identify the rush and find the right throw. It often leads to him being unable to get to it if the defense doesn’t declare their intent. But in the Super Bowl, Purdy did a very good job ona couple of plays mitigating the free rusher with good throws.
The unblocked pressures fall into a few categories in this game: 1) Where the quarterback should mitigate the pressure with better throws, 2) free rushers on boot play action passes, 3) plays where Brock hit the right throw to mitigate the blitz impact, 4) the two pass protection busts.
Blown protection assignments
At the start of the third quarter, the offense was unable to score after recording three straight three-and-outs to start the half, with their first drive starting at mid field after intercepting Patrick Mahomes.
The first play after the interception in the second half was a shot play on a play action concept called “burner.” This play action pass protection cost the 49ers at least two plays in this game, the other being the famous 3rd-and-4 in overtime, the one referenced above that Feliciano commented on. The culprit on this play is Aaron Banks, who blocked down inside and let the blitzing linebacker through.
I mentioned this on X (twitter) at the time and former offensive lineman Geoff Schawartz quote tweeted me saying basically I was wrong because there was no way they’d slide away from Chris Jones. But Jones slants inside, giving the down blocking guard an easier block to execute.
If Aaron Banks would have fanned out to his left, he would have picked up the blitzing linebacker as they had all the rushers accounted for along the front. In addition to this, we know Banks is wrong because every other linemen is stepping down to their left. Had Purdy not had the free rusher in his face, he might have hit Kittle who was open with a step on the defender or he could have checked down for some decent yardage.
On 3rd-and-4 on the last play of the season for the 49ers offense, the pass protection broke down again when, similar to the play way above with Banks, Spencer Burford stepped down the wrong way and allowing Chris Jones to get a free rush on Purdy.
It’s the same pass play action pass protection but just flipped. This would mean that Burford has the responsibility to fan out to his right to block Jones. Every linemen is stepping down to their right except Burford. If he so much as chips Jones, Purdy hits Jennings for a first down for sure and maybe a touchdown. After the game, Burford admitted that next time he needs to play within the scheme, alluding to basically freelancing and doing what he thought was right rather than doing his job.
There would still have been a free runner in Purdy’s face but it’s unlikely he affects the play because he’s coming from depth rather than the line of scrimmage. One more second and the 49ers might have been celebrating their 6th Lombradi trophy.
Free rushers on boot play action
This tactic is far more common now than it was just even a few years ago, the defense sitting on the backside of the play action away from the run action and not chasing with a defensive end or linebacker. It’s counted as a pressure, but it’s not a pressure that the offensive line can mitigate or control.
Typically, as in the play above, the backside of the defense would aggressively pursue the run action, leaving the quarterback free and untouched to hit an easy explosive play as in the play above.
Now, more and more teams are “greenlighting” the quarterback and allowing their backside defender to key on the quarterback no matter what the play call is. The idea behind this is to limit the explosive play potential by not allowing the quarterback to set up for a downfield shot play and forcing the quarterback to make a quicker decision, possibly forcing a throwaway or a quick check down.
The Chiefs forced an eight yard loss in the first clip where you can clearly see the 49ers were setting up for a downfield shot play. The backside defenders didn’t shuffle, they sat watched Purdy boot out to his right and immediately pressured him. On the second play, they sent another pressure off the boot side and forced Purdy to throw a short pass out to the flat for no gain.
Quarterback drop back pass game and free rushers
Bad scheme and bad throw
I’m going to combine numbers one and three from the categories way above this paragraph because they are nearly the same category but illustrate how Brock both shares blame for the bad and gets credit for the good. On these unblocked pressures, Brock both missed on a throw and made two good throws to beat the blitz. But on this first throw, I think we can say the scheme is the primary issue more than anything else.
The Chiefs are sending a cover-0 pressure with five defenders in coverage for five eligibles. It’s automatically up to the quarterback to mitigate the rush by finding the hot route when he diagnoses the play post snap. And he has several indicators: press man, no safety in the middle of the field, defender moving with Kittle pre-snap, and the entire rest of the defense crowding the line of scrimmage.
The pass protection, scat pass protection, is set to a half slide to the right and man blocking on the left. That by itself isn’t an issue. The issue is if that is the call, then the hot answer should be on the left side from Brandon Aiyuk or Christian McCaffrey. Instead, the hot answer is on the right side with a quick inside slant from the slot by Deebo.
They should let the free rusher come from the right side. Instead, Brock can’t see the free rusher and ultimately takes a blind shot from the rusher as he throws. The throw isn’t great and is in front of Deebo but Deebo was unable to get open on the lookie slant and the play was doomed from the start.
Bad read and bad throw
On the first play after the two minute warning, the 49ers went into a 2x2 formation with a condensed receiver stack to the right and a more spread out look to the left. Instead of keeping McCaffrey in the backfield as a pass blocker, Kittle was aligned to Purdy’s left in the running back spot.
The offense is running a double slant concept to the left with Jennings as the outside receiver and Aiyuk in the slot. The Chiefs show man coverage with a potential blitz from the right. Center Jake Brendel alerts the offensive line to the rush and I’m assuming putting the line in a “5-0” pass protection call since he’s now covered. A 5-0 call means that the offensive line will block the 5 most dangerous rushers across the front.
This would mean Kittle would have any potential 6th rusher but he has to scan for it. He thinks it’s Reid but it’s actually McDuffie blitzing from the slot. Kittle never gets there and never sees and ends up blocking a guy who’s already blocked. To be fair, Kittle never plays this position and Shanahan should not have had him there in a critical situation, though I get why he was there, to alert the offense to the Chiefs blitz and coverage.
But Purdy is also responsible here. Whenever a safety caps the defender in front of him, meaning to align directly behind him, it’s a dead giveaway that the defender closest to the line of scrimmage is going to blitz.
Purdy should have recognized that pre-snap but he didn’t. With the free rush in face, he tried to go to Jennings. Not a bad decision to throw to Jennings because the outside slant is usually always open against two deep safeties. And to be fair, there should not have been a free rusher. It would have been difficult to perfectly anticipate this happening when the protection called for 6 pass blockers.
Outlook
It’s easy to lie with stats and build a narrative for basically anything fans can think of. Fortunately the game tape rarely lies and shows that, in fact, the offensive line was not responsible for majority of those unblocked rushers but it feeds the narrative the 49ers offensive line is a below average unit, which is also not true.
In fact, one player is responsible for that narrative: Colton McKivitz, who was responsible for 35+% of the offensive line pressures per Pro Football Focus and had a 6.3% blown block rate in pass protection per Sports Info Solutions, the highest of any 49ers offensive line starter last season and nearly double the next highest player on the offensive line.
The 49ers had a 3.49% blown block rate in pass protection last season, 10th in the NFL. If McKivitz has half as many blown blocks as he did, their rate drops under 3%, among the teams with the lowest blown block rate in the NFL. Their average pass blocking efficiency in true pass sets was 94.5%, the same efficiency rating as the Chiefs.
The chasm between the top offensive lines in the NFL and the bottom is nothing more than sidewalk crack-sized chasm. There simply is not that much of a difference team to team and the talent pool of NFL offensive linemen is thin. The vast majority of teams do not have more than one very good to elite offensive linemen and the Eagles, who lost to the Chiefs in the Super Bowl in 2022, had two all pro offensive linemen on the NFL first team all-pros. So having them is not even a guarantee.
In part two, we’ll look at a couple more of the unblocked pressures in that game and what it looks like when a quarterback has the freedom to make protection changes.