The 49ers’ dominance after the catch isn’t an accident. Head coach Kyle Shanahan purposely constructed a roster full of pass catchers who can turn short throws into explosive plays to help mitigate the need for a superstar quarterback. Finding the former is much easier than finding the latter.
Quarterbacks in San Francisco have been tasked with the No. 1 job of being efficient and accurate in areas of the field that allow their pass catchers to generate additional yards with the ball in their hands. That specific job is why Jimmy Garoppolo had so much success. He was nails on short-to-intermediate throws, and the success of his receivers after the catch helped inflate his numbers.
When Brock Purdy stepped in as the starter last season he was given with the same job as Garoppolo and every other QB who’s stepped in under center for the 49ers during Shanahan’s tenure. The offense took off with Purdy at the helm though. It didn’t look substantially different, but suddenly San Francisco started racking up 30 points per game and Purdy launched himself into the Offensive Rookie of the Year conversation despite starting only five regular season games.
Purdy’s mobility in the pocket and his ability to extend plays certainly helped, but the numbers show there was more to it. There are a couple of things Purdy did just a little more effectively than Garoppolo that helped this version of the 49ers’ offense reach a new level without any major changes.
Let’s look at those numbers:
(Note: Trey Lance isn’t included in the stats here because of the limited sample size he has as the 49ers’ quarterback).
Deep passing
It’s not that Purdy was winging it deep every chance he got. According to Pro Football Focus, 11.6 percent of his attempts were throws 20-plus yards downfield. That puts him in the middle of the pack league-wide. However, it’s a pretty substantial uptick from Garoppolo’s 9.1 percent which ranked 31st in the NFL.
The bigger and more important change though was the efficiency from the QBs on those throws. Purdy attempted just one fewer deep throw than Garoppolo, but completed three more of them. He also converted four of those tosses into touchdowns compared to just one for his predecessor.
Deep ball completion rate lines up roughly with three-point percentages in the NBA. Purdy’s 40.7 percent completion percentage on throws 20-plus yards down the field is very good, and ranked 12th in the NFL last season.
We aren’t going to see a version of the 49ers’ offense where they’re consistently pushing the ball 20-plus yards, but they don’t need that. Purdy is a bigger threat to not only take those shots, but complete them. It’s another layer of the 49ers’ offense defenses have to defend, which helps open things up in the short-to-intermediate areas they want to work.
Intermediate throws
Speaking of short-to-intermediate areas of the field, this is the area that could see the most substantial upgrade for San Francisco. Garoppolo was fine 10-19 yards beyond the line of scrimmage. Last year he threw 19.2 percent of his attempts into this area and completed 62.7 percent of them. Purdy’s attempt rate was basically the same at 19.7 percent, but he completed a whopping 80.4 percent of his passes in the intermediate range. That mark led the league by 12 percentage points. The distance between Purdy and No. 2 was the same as the distance between No. 2 and No. 30.
This efficiency will likely regress a bit in 2023, but the improvement is another reason for the 49ers’ uptick in offensive output with Purdy playing QB. That ability to push the ball down the field even a little more often and a little more efficiently gives defenses more areas of the field to worry about when defending San Francisco.
Outside the numbers
A key wrinkle for San Francisco in the post-Garoppolo era is a greater penchant for throwing outside the numbers. That wasn’t something Garoppolo was necessarily averse to, but he was certainly better and more apt to throw it in the middle of the field.
Purdy wasn’t one to wing it to the boundaries more often than Garoppolo, but he specifically threw it short (0-9 yards beyond the line of scrimmage) and to his left 11.6 percent of the time. More than 17 percent of his throws went outside the numbers left thanks in part to that short-left number.
For comparison, Garoppolo went left on 14 percent of his throws and right on 13.4 percent. For Purdy those numbers were 17.3 percent and 11.5 percent, respectively.
This is where Purdy’s scrambling really comes out. He had a tendency last season to spin out of the pocket to his left. That led to a slew of short throws that are completed outside the numbers at pretty good efficiency. The 49ers aren’t likely to make a major change where they abandon the middle of the field. That’s a key area for them in creating yards after the catch. However, having a quarterback who can more often force defenses to defend the boundaries will help keep them from sitting on throws in the middle and taking away the offense’s bread and butter so easily.
Throwaways
Throwing the ball away is typically a better option than taking a sack. It was not one of Garoppolo’s strengths. His career-high in throwaways was in 2021 when he threw it away 15 times on 556 dropbacks. In 2020 he threw it away just once on 155 dropbacks, and in 2019 he did it 14 times on 589 dropbacks. Last year he was at four on 328 dropbacks before getting hurt. By comparison, Purdy dropped back 259 times and threw it away 11 times.
This may not seem like a huge deal, and in a vacuum the act of throwing the ball away isn’t a positive. However, a throwaway typically replaces a sack. That means a second-and-4 becomes third-and-4 with a throwaway instead of third-and-long with a sack. It’s not a coincidence that leaders in throwaways each year are some of the game’s best, most-seasoned QBs. Just the act of living to fight another down can make things easier on the offense overall.
Next step
All of this is of course doesn’t guarantee success for Purdy and the 49ers moving forward. First, he has to get healthy. Then he has to be confident enough in his elbow to play at a high level, and then he has to avoid regressing as his sample size increases.
These numbers do help tell the story of why the 49ers are so bullish on the final pick of the 2022 draft. He executed their specifically-designed offense at a higher level than Garoppolo did and helped unlock new areas of the field in the passing game.
San Francisco’s offense is always going to run through its weapons like Christian McCaffrey, Brandon Aiyuk, Deebo Samuel and George Kittle. Purdy’s skillset just allowed those players and Shanahan’s offense to be more effective than it had ever been.
