49ers Film Room: Brock Purdy shows he can hold the 49ers offense together the remainder of the season

49ers are down to their 3rd quarterback this season heading into week 14 and Brock Purdy will now have a chance to prove that Sunday versus the Dolphins was no anomaly.

49ers quarterback Brock Purdy, the last man taken in the 2022 NFL Draft (known as Mr. Irrelevant), suddenly became the most relevant person on the first place in the division 49ers. He was QB3 on the depth chart to start the season and battled for that spot with veteran Nate Sudfeld all of training camp. He was promoted to QB2 by default when Jimmy Garoppolo was thrust into the starting role for Trey Lance in the first quarter of week two.

In the first quarter against Miami, in roughly the same area of the field as Trey Lance, Garoppolo sustained a season-ending foot injury on a sack on third down. Purdy, the third quarterback to see the field on a team with a roller coaster of a quarterback situation for the last year, will start as QB1 on Sunday versus the Tom Brady-led Buccaneers and against the league’s 8th most efficient defense per Football Outsider DVOA metric and the 8th ranked defense in EPA per play.

Brock leads the 14th most efficient offense per DVOA and the 8th most efficient in EPA per play, turning what should have been a student versus mentor game with Garoppolo and Brady into a game where Brady has the luxury of facing yet another rookie quarterback.

On Sunday, Purdy was 25-37, 210 passing yards, tossed two touchdowns, and threw one interception. Fans were shocked by the amount of passes attempted but this was primarily because the 49ers faced 19 third downs throughout the course of the game where Purdy was asked to pass on 13 of them.

On his passes alone, Purdy faced an average of 3rd and 6 to convert. They faced an average of 7.6 yards to convert across all third downs, so it makes sense why the passing stats seem inflated. The Tampa Bay defense is allowing the 9th lowest third down conversion rate in the NFL to opposing offenses. Majority third and long situations against them will not end well for Kyle Shanahan and his new quarterback. They have to be better on 1st and 2nd down in this game.

Brady now has a 23-6 record in games he’s played in where the opponent started a rookie quarterback. Can Purdy be his 7th loss to a team led by a rookie? I think it can and here’s what he did well and what he will need to improve on if they are going to take down the Brady-led Buccaneers.

Timing/anticipation throws

The 49ers have the weapons on offense to take the pressure off of Purdy but he will still have to hit throws that are there and do it with timing against a top ranked defense. Against Miami, he showed he knows where to go with the ball if given a chance.

Third quarter, 3rd and 5 @ SF 39, 13:39 remaining

On this play, Purdy displayed good timing and anticipation to hit a throw over the middle of the field on a dig route to Jauan Jennings.

The route combination is a dig route and choice out route to stretch the underneath coverage and create a throwing window for the dig route.

The defense is playing a spot drop nickel cover-9 where the safety rotation is to the weak side flat away from the passing strength and away from the nickel defender with the underneath defenders dropping to the sticks and trying to take away the middle of the field throws.

The throw here would require some anticipation since the defenders are seeking to take away what the 49ers love to do and they do it well: throw over the middle of the field. Purdy reads the safety rotation and knows right away that he has the dig route behind the weak hook/”3-receiver hook” defender to his left side. The ball is out of his hand before Jennings ever uncovers from the linebacker.

Reading progressions pre and post snap

Perhaps one of his biggest strengths in this game was reading progressions and Shanahan likes to call the same plays more than a few times in a game for his two young quarterbacks to help them with the picture they are seeing post snap.

The 49ers called a 4-man snag concept with a swing pass, a corner route, an “over the ball” route, and a backside slant route if the quarterback likes the match-up 1-on-1 and sees bump or press coverage.

On his first three attempts on this concept, Purdy read the pre-snap 1-on-1 matchup that Aiyuk had versus the corner and threw the quick slant to him, two were completed, while one was off target. Purdy demonstrated good pre-snap recognition of the matchup across the field.

In sequence early in the fourth quarter, Shanahan called it three times in a row. One was in the cut-up above with the quick slant to Aiyuk. In the two plays after that, Shanahan changed up the personnel groups and ran the same concept.

In the first clip, Purdy surveyed the field, first looking for Aiyuk but the Dolphins defense dropped a defender to the flat to help on his slant. Purdy then scanned across, feet in sync with his eyes before finally settling for the checkdown to Deebo.

In the second clip, Purdy found Deebo again, this time Deebo was running the snag route while McCaffrey was running the swing. Purdy quickly looked to the slant, then across and found Deebo in a small window where Deebo was able to catch and get upfield for a few yards.

Blitz recognition

Perhaps his best throw of the day came when he beat the blitz on third down to George Kittle on a short post route over the logo of the field. It was the same pressure package that recorded the sack on Jimmy Garoppolo in the first quarter, the play he got injured on.

The 49ers are running their “chevy” concept, a two man route combination to the right with a skinny post and a “tony” route which is just a stick route out of the backfield with the option to cut outside versus the leverage.

The defense has seven defenders hugged up to the line of scrimmage and presnap this looks like a cover-0 blitz. Purdy has to figure out where the rushers are coming from. The pass protection slides to the left to the widest and most dangerous rusher on the offense’s left edge.

The rush only comes from four defenders but since the offensive line slide to the left, the free rusher comes off the right edge of the offense, and this makes him Purdy’s responsibility. Purdy sees it and fires the pass just before he gets hit. From snap to throw, he released the ball in 1.78 seconds. That’s some fast recognition. 

In his Football Morning in America column on Monday morning after the Sunday games, Peter King wrote that he talked with Shanahan about this play, saying:

“I thought this was Purdy’s play of the game,” I (Peter King) said.

“I did too,” Shanahan said. “Especially with what they were doing to us. They were coming after Brock and doing a good job of taking our quick throws away. This was a huge job of Brock signaling something to change the route [for Kittle].”

Purdy recognized the blitz pre-snap and made a route adjustment on Kittle’s route to shorten the post route. The route is normally run at 6 steps before breaking to the post. Kittle shortened his route to 5 steps.

The change is significant because on a 6-step post route, the inside foot is the lead foot. On Kittle’s route, notice how he changes his stance to the outside foot up, this shortens the route to a 5-step route by the receiver. The adjustment was likely communicated pre-snap in the huddle because there is nothing on the all-22 to suggest it was made at the line and Kittle lines up right away with his outside foot up.That’s one hell of an adjustment.

Off schedule throws

It seemed like Purdy was running for his life on some plays too. Purdy was under pressure on 14 dropbacks and faced the blitz on 12 per Pro Football Focus. On a few occasions he caught the snap and was immediately running away from pressure.

He showed he has the athleticism to out run the rush. In both plays above, he’s able to beat the defenders to the edge and get the ball off to his receivers.

Accuracy

He also threw some incredibly accurate passes as well.

On this play, which I have written about extensively, he hit Deebo over the middle on the “drift” route on play action with a pass that was far enough in front of Deebo that the defender couldn’t knock it away.

Here, he threaded the needle to Christian McCaffrey between a triangle of defenders that McCaffrey ends up dropping. He threw to his outside shoulder so the pass wouldn’t lead him into the defender coming across to hit him. Another skillfully placed pass.

Looking for the deep throw

On Sunday after the game, Shanahan stated:

“I think Brock naturally looks a lot more often for the deeper one than the shorter one, which is awesome. Sometimes, it helped today. In a couple early, I thought he missed just having someone quick right there and just trying to look for something deeper and then ran out of time to come back to the short one. You like that about a guy’s personality. You want that much more than the other way.”

His aggression was on full display despite the outcome of these two plays. In this first play, a play action passing concept with a deep crosser and deep post on the same side, Purdy looked for the deep post near the end zone and might have completed an explosive pass play but he left the pass just a bit behind Deebo when it should have been a few more yards out in front where Deebo could run to it.

On his interception on a throw to Aiyuk, he had Aiyuk singled up 1-on-1 with Xavien Howard and took his chances with that matchup. The pass needed to be placed a bit more outside on Aiyuk’s back shoulder but nonetheless, the rookie seemed unphased by the matchups and seemed willing to let his playmakers go make plays. Eventually he will hit a few of these throws for an explosive play.

Still, these plays didn’t kill Shanahan’s confidence. In Wednesday’s press conference, Shanahan also stated, in response to a question about Purdy’s aggressiveness:

“I like when a play is there that guys aren’t scared to make it, they don’t hesitate, they don’t take a second look at it. They let it rip and they worry about it after. A lot of guys who just guess do that too, so you have to find out whether they’re being aggressive or just if they’re deciding then to do it or if they’re deciding on Wednesday and then that’s a big difference, but Brock has been very good with it. He can explain what he sees and that’s why we got a lot of confidence in him.”

Where he needs to improve

His biggest issue on Sunday were inaccurate throws. Pro Football Reference charged him with 5 bad or poor throws for 14% of his passes.

Nearly all of these can be corrected with reps and time over the next several as he builds a rapport with the first team receivers.

Outlook

All things considered, Purdy played really well after being thrown into the fire. With a full week’s prep as QB1, he should be even more ready and we’ll get a better picture of how he handles the job the remainder of the season. This will undoubtedly be a good test for the rookie going against one of the league’s best defenses.

The 49ers have no choice but to play Purdy unless there’s a slight or slim chance Garoppolo or Lance could come back. I wouldn’t count on that as both seem unlikely to occur despite the hype. Will Shanahan let him be aggressive or will he try to rein him in to limit the mistakes? If this Sunday is any indication, it seems like Shanahan will give him more than his fair share of opportunities to be aggressive.