David Lombardi of The Athletic says Rams have found success “without great QB play”
A San Francisco 49ers beat writer—David Lombardi of The Athletic—fired off a white-hot take on X this week.
Lombardi posted:
The Rams have executed their roster renovation and successful turnaround with Matthew Stafford ranking #15 in QB efficiency over the past 2 seasons. So LA has done this without great QB play, and Stafford isn’t getting younger.
The 49ers have the luxury of Brock Purdy, who’s ranked #1 since entering the league, at the opposite end of his career
Let’s break this done one part at a time.
Credit where credit is due
It’s true that Purdy is entering the prime of his NFL career as Stafford wraps up his final years as a professional quarterback. You can never tell how far off the horizon the cliff is for players, especially at the QB position.
We’ve seen Tom Brady and Aaron Rodgers play at a high level into their mid-40’s. Others like Kirk Cousins and Matt Ryan watched their abilities fade rapidly.
We don’t know what the end will look like for Stafford. The Los Angeles Rams don’t either, which is why they are comfortable taking his deal one year at a time and even letting the veteran explore his options outside of Los Angeles. It’s undeniable that Stafford’s play took a step back in 2024; however, this was far from the best supporting cast he’s enjoyed during his time with the Rams.
While the 49ers will benefit from Purdy’s youth—assuming his looming contract extension crosses the finish line this offseason—for years to come, the affordability of his rookie deal is short-lived. San Francisco spent the early parts of the offseason shedding talent in anticipation of Purdy’s payday. Can Purdy continue to play at a high level when he no longer has Deebo Samuel and/or robust pass protection? He must elevate the remaining talent and continue to do so even after the playing days of George Kittle, Trent Williams, and Christian McCaffrey are over.
While Lombardi says Purdy is a “luxury” for the 49ers, the reality may be more nuanced than he is letting on. Purdy’s youth is certainly a positive; however, his second contract will be a bet that the quarterback can create even when he doesn’t have a superstar roster on offense. It’s a true double-edged sword.
Is Brock Purdy better than Matthew Stafford?
It’s not entirely clear which metric the original post is referring to when it cites “QB efficiency”. Based on subsequent posts and additional context, we can infer that Lombardi was using Expected Points Added (EPA) on a per play basis.
These are the unadjusted EPA per play measures with overall rankings for Stafford and Purdy over the 2022, 2023, and 2024 seasons according to SumerSports. I applied a 240 snap threshold for each year.
Matthew Stafford
2022 – #44, -31.7 EPA/play
2023 – #10, 0.09
2024 – #16, 0.06
Brock Purdy
2022 – #9, 0.13 EPA/play
2023 – #1, 0.29
2024 – #5, 0.18
So yes, Lombardi’s point that Purdy has been the more efficient quarterback since he came into the NFL is accurate and fair. Does that tell the whole story? There are some common criticisms of using EPA to evaluate QB play and more context may be necessary to understand the full picture.
EPA is mostly a team-based metric
EPA seeks to measure the change in estimated points a team will score based on the outcome of a play. The outcome of a single play is influenced by all 11 players on the field in addition to the scheme and play calling introduced by the coaching staff.
It can be difficult to discern fault or attribute credit to those responsible for outcomes. A quarterback could throw a perfect pass that is dropped by the receiver. We’ve also seen receivers turn drops into interceptions. If the team allows a sack, did the passer hold the ball too long or did the offensive line lose quickly?
It’s fair to use EPA to evaluate quarterbacks because they touch the ball every single play and there’s only one on the field at a time. The success of the passing game is directly attributable to the person under center, though alone EPA does not tell the whole story.
EPA is highly sensitive to turnovers:
The oldest fact in football is that turnovers will lose or win you games. Win the turnover margin and you will have a chance as the clock winds down.
EPA reflects this reality, and perhaps even does so too much. While Pro Football Focus (PFF)’s turnover-worthy play metric attempts to discern whether there was a potential for a giveaway and attributes fault to the quarterback, EPA only looks at whether there was a turnover. Was there a quick strip sack that would be been near-impossible for the quarterback to evade? Were there multiple interceptable passes that fell harmlessly incomplete?
When you focus on outcomes instead of process you will lose important context, especially when dialing in on the performance of a single position.
What do other metrics suggest about the two QB’s?
These are the PFF passing grades, big-time throw (BTT) rates, and turnover-worthy play (TWP) rates for each quarterback over the same time period. It tells a different story then the EPA per play.
Matthew Stafford
2022 – 67.6 PASS; 4.8% BTT; 3.5% TWP
2023 – 86.0 PASS; 6.3% BTT; 1.9% TWP
2024 – 73.3 PASS; 4.2% BTT: 3.7% TWP
Brock Purdy
2022 – 75.1 PASS; 3.1% BTT; 3.0% TWP
2023 – 81.5 PASS; 5.5% BTT; 3.2% TWP
2024 – 76.3 PASS; 3.1% BTT; 3.0% TWP
Stafford’s career BTT and TWP rates are 5.2% and 3.2%, respectively, which helps stabilize some of the swings in these metrics from recent years.
Still, the end result is that these quarterbacks are more similarly than is made clear in the media landscape. Purdy is a good, young quarterback. He puts the ball in harm’s way at a higher frequency than you’d like to see—and Stafford is not exempt from that criticism. Purdy can also contribute to offensive production with his legs, and that’s not a bonus the Rams will get from Stafford.
But the biggest difference between Purdy and Stafford is the fact that LA’s signal caller can manufacture big-time throws more frequently. That helps at the margins when receivers are adeptly covered and the team can still find ways out of tight spots. This is a measure of how often quarterbacks create outside of the structure of the offense, and Stafford is simply better at this than Purdy.
The bottom line
These quarterbacks are closer together from a productivity standpoint than we often realize. The 49ers are well-suited long-term with Purdy while the sand is running out on Stafford’s tenure with the Rams. Lombardi hit this nail on the head in his X post.
However, it’s unwise to rely solely on EPA to evaluate the play of quarterbacks given the common criticisms of this metric. EPA per play suggests Purdy is head and shoulders better than Stafford—and for that matter perhaps the most efficient passer in the league. The truth is more complicated.
The Rams simply have not enjoyed success in recent years amidst a roster rebuild despite Stafford. They’ve often won because of him and his ability to add value outside of the offensive structure. Whether Purdy can accomplish that as his supporting cast diminishes remains to be seen.
