The Green Bay Packers and San Francisco 49ers will meet in the divisional round for the second time since 2022. Last time, San Francisco came into Green Bay as the 6th seed after upsetting the 3rd-seed Dallas Cowboys (sound familiar?) The script flipped this time, where the 7th-seed Packers travel to Santa Clara to the 1st-seed 49ers after beating…the Dallas Cowboys.
In that 2021 season, the 49ers season was not unlike the Packers in 2023. Both teams struggled early in the season before finding their way in the back half of the schedule.
That year the 49ers finished 7-2 in the last half of the season and won in Los Angeles in overtime to grab the 6th seed. This year, the Packers finished 6-3 over that same span of games from weeks 10-18 and earned their spot at the table by beating the Bears in week 18 in a must-win game.
That’s where the similarities end though. In a sport with so few data points and small sample sizes, there’s bound to be a few similarities. But the two team’s paths to get that point and where each unit’s offense and defense ranked were almost night and day different.
Packers defense vs 49ers offense
Brock Purdy in 2023
The 49ers had just come off a Super Bowl run in 2019 before a devastating 2020. The Packers this year are fresh from the grip of Aaron Rodgers, whose 2021 playoff performance versus the 49ers all but signaled the beginning of the end for him in Green Bay.
On offense for the 49ers, they come in ranked as the NFL’s most efficient offense where they rank #1 in EPA per play and #1 in offensive DVOA. Since 2019, head coach Kyle Shanahan has fielded the 4th most efficient offense overall in EPA/play. This year it’s no mystery why. The addition of Christian McCaffrey has unlocked the offense’s potential and sent them to new heights.
But we can’t forget quarterback Brock Purdy, who in his own way has elevated the offense beyond what Jimmy Garoppolo was ever able to do. Purdy has league-average arm strength but that hasn’t stopped him from pushing the ball down the field when the opportunity arises.
And he’s been pretty efficient and accurate while doing so. Per Pro Football Focus (PFF), Purdy leads the NFL in passing grade on deep throws (throws 20+ air yards downfield), is ranked 7th in big-time throws at that distance (PFF), 5th overall in big-time throws (PFF classifies a big-time throw as “a pass with excellent ball location and timing, generally thrown further down the field and/or into a tighter window”), is 2nd in the NFL in completed air yards per pass (per NFL NextGenStats), and leads the league in EPA/play (per RBSDM).
His ability to go off-script or off-schedule when a play breaks down is also light years above what the 49ers have had at the position since Colin Kaepernick.
His athletic ability so far has been able to overcome sometimes subpar pass protection and at other times enabled him to beat a free rusher. Purdy has raised the level of play of the offense for the 49ers far more than his predecessors ever did under Shanahan. For one thing, on outside of the pocket throws (excluding play action), Jimmy Garoppolo ranked 16th in grading in 2022. In 2023, Purdy ranked 7th. On scrambles, Purdy registered 17 scrambles that went for 15 first downs, 88%.
Purdy has also thrown 11 interceptions this season (4 in one game) and while some of those turnovers are just bad luck on tipped balls, some have been egregious and were just waiting to happen.
Through their five-game win streak to start the season, Purdy ranked 9th in “turnover worthy play” rate (TWP) and jumped up to 6th through week 8 after their 3-game losing streak. In weeks 10 through 15, he dramatically dropped his TWP rate over the course of those six games to 1.1% yet only threw two passes considered “turnover worthy.”
That changed in week 16. He recorded two TWP’s despite throwing four interceptions, had previously tossed two interceptions in recent games. One might argue that TWP’s are a useless or pointless stat to track or cite but they are a context-driven stat. They track passes that hit a defender in the hands that have a good chance of being intercepted, whether it was or not. So not all throws are turnover-worthy.
TWP’s give us context on poor decision-making or bad ball placement and allows us to get the full picture of a player. Defenders failing to catch passes the quarterback throws to them doesn’t absolve the quarterback of a poor decision or inaccurate pass. These data points suggest a pattern and that we shouldn’t be surprised when turnovers happen. Of course they do, the predictors were always there.
49ers passing game
In the passing game, the 49ers are not that much different from the Packers. They run a lot of the same concepts and just get to them in different ways. The 49ers most used personnel grouping is 11 personnel (39%, 1 running back, 1 tight end, 3 wide receivers) followed by 21 personnel (36%, 2 running backs, 1 tight end, 2 wide receivers). Out of those, they pass 69% in 11 personnel and 50% of the time in 21 personnel.
Their two favorite non-play action passing game concepts consist of some type of dig route over the middle or choice route concept with McCaffrey.
The in-cut dig routes are Purdy’s money maker because he throws them with excellent timing, accuracy and anticipation, like on these two throws from their Dallas game in week 5. The ability to layer the ball over the hands of linebacker Leighton Vander Esch.
He can also throw the dig route versus man coverage. This is also a good look at how Shanahan’s offense uses its personnel to create space to throw as well. The attention McCaffrey draws in the passing game creates some of these windows. But Purdy does the rest and against man coverage, the pass still has to be catchable and accurate on the receiver’s body.
In the play-action passing game, their preferred drop-back pass concept is the dagger and drift concept, just like the Packers.
The 49ers are running play-action dagger here out of 22 personnel from a shotgun formation in week 10. Aiyuk is the motion man from left to right and motions to the right to run the dagger route. Kittle is running the deep “thru” route. The Jaguars are in zone cover-3 but have a third safety in the game.
Kittle is first in the progression as Purdy drops back to throw. The middle hook defender drops deep and sinks under Kittle’s route so Purdy moves to the dagger behind him to Aiyuk. Aiyuk gives a nice move with a 1-step stem outside to the defender to get him to turn his hips, and continues up vertically until he cuts off the outside leverage inside across the field.
Where the 49ers offense struggles
The 49ers offense has struggled in the passing game versus split safety coverages, primarily cover-6. Purdy’s worst passing comes against cover-6, which is cover-2 the run strength side of the formation and quarters coverage to the pass strength. The Packers' defense’s best pass snaps occur when they play cover-6 or cover-8 (reverse cover-6).
In week 16 versus the Raven, he threw four interceptions, most of which I classified as either not his responsibility and were bad luck. But his first interception was 100% his fault and it took the wind out of their sails and seemed to set the tone for the entire half after that.
The play call is a double post concept to the two receiver side with Deebo in the slot and Brandon Aiyuk outside with Deebo on the crosser and Aiyuk running the dagger. George Kittle and Kyle Juszczyk are aligned on the offensive line in a closed nub formation to the right. Christian McCaffrey is the running back who swings out wide left post-snap.
The Ravens are in cover-6, quarters coverage to the passing strength and cover-2 to the closed side of the formation. Safety Kyle Hamilton (No. 14) is the cover-2 safety to the offense’s right.
There’s no deep route challenging Hamilton on that side of the field so he’s content to sit and watch the routes develop and key’s on Purdy reading right to left. The primary side of this concept is the premier look versus the quarters side. The split safety coverage shell can squeeze the inside deep crosser/post from Deebo and leave the outside post 1-on-1 with the corner.
Purdy drops back and sees split safety coverage and comes back to Deebo too late and throws the pass too far inside with Hamilton squeezing the route from the opposite hash. He’s able to step in front of the route for the interception. Shanahan stated post-game that Purdy misread the coverage. I also think he was late on the throw and think he had a chance to hit Aiyuk as the second in that progression. Either way, there was no reason for a risky pass across the middle like that.
Packers' best pass coverage
One of the Packers' most efficient pass coverages was cover-6 (which probably includes some cover-8 snaps as they are generally the same). If the Packers have a plan to disrupt the 49ers passing game, then part of that plan has to include strategic use of this coverage shell to take away the windows Purdy likes to throw into and force him into quicker decisions.
The Packers created a few turnovers with this coverage shell. In week 9 versus the Rams, safety Anthony Johnson caught a tipped ball from cornerback Jaire Alexander. On his interception, the Packers were playing cover-8, which is the opposite of cover-6. It’s cover-2 to the pass strength and quarters to the weak side. In cover-6, the nickel goes to the quarters side. In cover-8, the nickel goes to the cover-2 side.
In cover-8, the slot defender plays the vertical curl zone and has a squat/flat corner to his side and a deep safety over the top. The vertical curl defender is in a prime position to not only help play a bracket coverage, but can also peel and cut off another route in his field of vision.
On his interception, he’s lined up as the deep half-safety in cover-8. Alexander sits on the underneath route before sinking to the corner route. Rypien was unable to layer the ball over Alexander so Alexander tips up and Johnson is there to make the interception.