WCF Film Room: Breaking down Brock Purdy’s six sacks in week 2

Brock Purdy was sacked 6 times in week two. Which ones were on him and which ones were the result of some other factor?

For the second straight season, the 49ers lost a close one on the road to the Vikings in week 2 by a score of 23-17. Last year it was 22-17. This year it was the same story, a Brian Flores defense frustrating a lifeless Kyle Shanahan offense with well-timed blitzes and disguised coverages. And it led to six sacks on Brock Purdy. According to Pro Football Focus, the Vikings blitzed Brock Purdy on 51.1% of his passing snaps.

Six sacks does not help dispel the narrative that the 49ers have a bad offensive line. At least four of the sacks were primarily on Purdy, whose time to throw under pressure was 3.47 seconds and 3.08 versus the blitz. The line was giving him ample time to throw combined with his ability to extend plays. At least two sacks were primarily credited to the offensive line though.

Purdy even stated on Thursday that “​​There were a couple of plays where I dropped back and for me I just wasn’t on top of my progressions and getting off certain reads and holding onto the ball a little bit in certain situations and plays.”

For as much as Purdy might have missed a few plays or the line might have had a few busts, defensive guys still paid too, and Brian Flores still deserves a ton of credit for the game plan he installed for this game against the 49ers. Flores is known for exotic looks like showing cover-0 pre-snap and bailing to a Tampa-2 zone coverage post snap. But this season, he’s showing split safety coverages on the majority of his snaps according to Cody Alexander at Match Quarters.

1st sack, 2nd quarter, 15:00, 2nd and 10

Purdy’s first sack came at the start of the second quarter. The 49ers motion to their favorite 4x1 snag concept with the first read coming from Kittle on the back side as the single receiver running a quick slant.

The Vikings pre-snap shows a two-deep shell coverage with safety Harrison Smith rotating down late in the pre-snap and continuing post snap. Purdy gets a man coverage indicator when the linebacker travels with Deebo’s motion. At the snap, Purdy’s eyes are on the deep safety too long before he comes to Kittle.

He came back to the middle to Brandon Aiyuk on the “over” route but didn’t throw it when he could have. His internal clock was ticking and he took off to the right to make a play but ended up taking a sack.

Sack responsibility: Purdy.

2nd sack, 3rd quarter, 12:23, 1st and 10

On 1st and 10 here after halftime, Brock sacked himself with a scramble and dive at the line of scrimmage. He had a play similar to this in the preseason where he took a two yard loss running out of bounds on a scramble drill.

The 49ers are running a flat-7 concept to the right with the receivers and are using Juszczyk and Kittle inline to the left. Juszczyk motions to the right and the defense rotates late into a two-deep shell but no one follows him on the motion, a zone indicator for the quarterback.

The snap reveals a blitz from the offense’s left, a 5-man zone pressure. Kittle’s defender is locked man to man, the safeties are over the top protecting the shot play, and there isn’t a throw to the corner route up top, or at least one Purdy would feel comfortable making with safety nearly over the top. Brendel gets put on his face so Brock escapes the pressure to the left and tries to extend the play.

He ends up diving at the sticks but gains zero on the play so it’s recorded as a sack. Technically, this is on Brock too but it’s the same as an incomplete or a throwaway. I’m a little more bullish on this being quarterback responsibility because of the potential for lost yardage when a throwaway is probably the right answer once outside the pocket with no one open. But he didn’t lose yards.

Sack responsibility: Purdy.

3rd sack, 3rd quarter, 10:59, 3rd and 12

Two plays later, Purdy was sacked again and this is one of the ones Shanahan mentioned “I believe one was from a hot that we didn’t throw.” There were actually two sacks on missed hot reads, and we’ll get to the other one, but this is definitely a missed read by the quarterback.

The offense is running a staple concept they kill teams with on a regular basis, the deep dig over the middle. It’s as much a staple play for Shanahan these last two seasons as it is the outside zone. Purdy is nails on this concept. It’s a good high-low on the vertical hook defender in the slot and if had time, he might have gotten to the dig.

The Vikings are playing quarters behind a 5-man pressure. Juszczyk is the running back in the back field and leaks out because the offensive line has everyone accounted for in pass protection. The line is half sliding to the left because the center is covered with two pass rushers to their left along the offensive line versus two rushers to the right.

The Vikings slant their rush to the offense’s left and drawing Dominick Puni inside where his man picks Brendel. Puni can’t recover and loses track of the stunt the Vikings send inside to get a free rusher at Purdy. But while this is happening, there’s about four seconds for Purdy to make a decision and hit his checkdown over the middle. He doesn’t and takes the sack. Cannot hold the ball that long when the check down is right there.

Sack responsibility: Purdy.

4th sack, 3rd quarter, 6:49, 1st and 10

Another 5-man pressure, another sack. The Vikings found a half dozen ways to get five man pressures and play tight zone coverages behind it to close “spots” Purdy likes to throw to in the offense. Again here, the Vikings are playing a soft cover-2/2-read/2-palms coverage with a 5th rusher adding post snap from the second level.

Purdy motions Juszczyk to the left and no one follows. This is his first indication that there’s likely a blitz of some type because no one on the defense shifts with the motion and they’re not really disguising their intentions at this point except not giving any indicators where the blitz will come from.

At the snap, we see the offensive line in a full slide to the right with Trent Williams blocking back side the most dangerous defender, the blitzing linebacker. Purdy has responsibility for the free rusher at this point he should know is coming from somewhere and look to locate his hot in the flat to the right with Mason quickly or with Juszczyk on the back of the play. Instead, he tries to read out the progression and goes from Deebo to Mason.

He doesn’t pull the trigger with either one because of where Van Ginkel is sitting and reading the play. Credit to Van Ginkel for muddying up the play to the right side (top of the screen) but you’d still like the quarterback to read the pre-snap indicators a bit better and anticipate being hot as the Vikings blitzed 51% of the time in this game.

Sack responsibility: Purdy.

5th sack, 3rd quarter, 3:18, 2nd and 9

Here the 49ers get another 5-man pressure but the offensive line on the left side, in a rare bust, is actually responsible for this sack. They have six to block five with Mason as the check release into the flat.

The edge defender dodges the chip from and loops inside to the quarterback while the linebacker rushes the B-gap and picks off Trent and ricochets inside to sack Purdy. Banks is just too slow here and Trent is not on the same level to be able to pass off the stunt effectively. Sack responsibility: Williams/Banks.

6th sack, 3rd quarter, 2:15, 3rd and 15

This was Purdy’s second turnover of the game, a ball that slipped out of his hands and was recovered in the air by the defense. It was originally ruled an interception but was changed to a fumble in replay review because his hand was not going forward.

There were rumors of the Vikings stadium crew turning up the heat or that it was hotter than normal in the stadium, all unconfirmed at this point and it doesn’t matter. It was an unlucky turnover but the quarterback is still responsible for ball security at this point as he was not contacted off his blindside or anything like that and had clear vision for a throw.

Here’s what Shanahan said about the play:

“People sweat when they exercise hard or when they’re really hot. So yeah, that’s probably what made it slippery. But that’s stuff quarterbacks deal with every game, especially from center’s snap a lot, and quarterbacks get their hands wet from having to take snaps from centers, too, and sometimes ball carriers soak the ball also. So, there’s lots of things that go into it. But yeah, slipping has to do with things that make hands slippery.”

There is no correlation between hand size and fumbles like this, as this article from two years ago meticulously researched by the folks over at Mile High Report show. But these guys also play late in games sweating all the time so this is likely just protecting the quarterback with this statement. Which is fine, it was just an unfortunate turnover that is ultimately Purdy’s responsibility but was just dumb luck.

Sack responsibility: Purdy but is really just bad luck.