49ers midseason evaluation: Brock Purdys very good offense misses Trent Williams
The San Francisco 49ers offense has firmly taken the reins as the leading unit of this 2023 team. Through eight games, the attack ranks No. 3 in the NFL in expected points added (EPA) per play, trailing only the Miami Dolphins and the Buffalo Bills.
But efficiency splits show how badly the 49ers are missing left tackle Trent Williams and versatile receiver Deebo Samuel. The injuries to both occurred early in the 49ers’ Week 6 defeat to the Cleveland Browns, so they’ve neatly coincided with the team’s three-game losing streak.
49ers' team EPA splits by game
| Opponent | Offense | Defense | Special Teams |
|---|---|---|---|
+9.7 | +13.5 | -0.8 | |
+12.4 | -3.3 | -2.0 | |
+19.0 | +11.8 | -9.7 | |
+30.5 | -9.7 | -1.6 | |
+12.9 | +23.1 | -5.2 | |
-6.1 | +11.3 | -7.3 | |
+5.4 | -16.3 | +6.1 | |
+9.3 | -18.3 | +2.5 |
Source: TruMedia
Even without a healthy Williams and Samuel, quarterback Brock Purdy has been able to stabilize the offensive ship — it just hasn’t been sailing nearly as smoothly as before. He drove the 49ers into position for a win at Cleveland — the offense’s only inefficient game — and delivered positive performances against the Minnesota Vikings and Cincinnati Bengals.
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Giveaways did mar both of those games and contributed to the 49ers’ losses, but the team’s defense holds much greater culpability for those past two defeats.
GO DEEPER
49ers midseason evaluation: Where Chase Young can boost languishing defense
We evaluated the defense yesterday. It’s time for a deeper dive into the offense, where examining performance in terms of the five-game winning streak to open the season versus the three-game losing streak to lead into this bye week again makes the most sense.
The 49ers, who scored 30 or more points in all of their first five games, have been held to only 17 points in each of the past three contests. A look under the hood of their offense’s performance, however, shows the drop in scoring output has been significantly greater than the drop in efficiency — an indicator the defense’s failures deserve more blame for the losing streak.
49ers' offensive efficiency splits
Source: TruMedia
The offense has only dropped from No. 1 to 4 in success rate per dropback, or the percentage of pass plays that have netted a positive EPA. It’s the 49ers’ run game that’s suffered on a raw usage level — dropping from 32 to about 19 carries per game — and on a per-play efficiency basis.
“Besides turnovers, I don’t think we’re running the ball enough,” 49ers tight end George Kittle said after the 49ers managed only 17 carries from their running backs against Cincinnati. “And situationally, I don’t think we can run the ball because of the situations we’re putting ourselves in.”
This circles back to the lack of complementary execution, which calls for establishing a lead and then holding it by exerting downhill control of both lines of scrimmage. The 49ers have been particularly bad at that recently — for multiple reasons. Running back Christian McCaffrey’s early fumble was damaging against Minnesota. The defense stopped holding up its end of the bargain after that.
The 49ers haven’t been able to control the game script well enough to run the ball more with Christian McCaffrey. (Stephen Maturen / Getty Images)That’s thrust Purdy into come-from-behind situations, during which he’s simultaneously engineered success by generating explosive plays — many of them outside of the offensive structure — and committed turnovers that have derailed the 49ers’ comeback bids.
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“Brock’s been one of the reasons we’ve been in these games these last two weeks, and he has done some unbelievable stuff,” 49ers coach Kyle Shanahan said. “But I also will say, when you’re down some points and you’ve got to get back into it, that quarterback is going to win it or lose it. That’s part of the position because he’s got to make some big-time plays just to get us back in that. And I thought Brock made some big-time plays versus Cincinnati, a number of them scrambling, a number of them with his throws. And he was one of the reasons that we got a chance to at least be within one score at the end. And he’s one of the main reasons we believe we’re going to be able to go down and score.”
QBR rankings
Ultimately, the best way to evaluate Purdy is on the aggregate. He ranks No. 3 in QBR. He’s been accurate and efficient against all coverages to all levels of the field. In fact, Purdy’s passer rating of 142.2 leads all NFL quarterbacks on throws of 25 yards or more downfield. Perhaps most remarkably, Purdy has generated the fourth-most EPA per QB scramble, more than Mahomes, the Philadelphia Eagles’ Jalen Hurts and the Chicago Bears’ Justin Fields.
That sets up what might be the most significant takeaway of the early season: Purdy simply hasn’t been a physically limited quarterback, as had been widely assumed — probably because the 49ers nabbed him with the last selection of the 2022 NFL Draft. Purdy has undoubtedly made some errors recently when the 49ers have been trailing — his interception rate of 2.2 percent ranks in the middle of the pack — but his dual-threat production has also raised the ceiling of Shanahan’s offense.
The team believes Purdy’s talents will continue paying explosive dividends over the back half, but it’s imperative the 49ers rediscover their rushing efficiency so he and the offense can consistently regain control of game flow. That’s an indispensable part of Shanahan’s formula because his versatile personnel specializes in strangling opponents on the ground before stretching them with play-action passes.
The 49ers must be better up front, though.
49ers' offensive line performance
Pass-block efficiency and run-block grades ranks are from Pro Football Focus. Players are ranked against qualifiers at their position groups. There are about 60 qualifying tackles, 60 qualifying guards and 30 qualifying centers.
Center Jake Brendel has been significantly worse this season than last, dropping from No. 4 to 23 in pass-block efficiency and several spots in run-block grade (he couldn’t handle Cincinnati tackle D.J. Reader on a failed third-and-1 that set the tone for that game). Left guard Aaron Banks is dealing with turf toe, so veteran backup Jon Feliciano will likely have to step in to keep the line moving. And although right tackle Colton McKivitz is scoring better in pass-block efficiency than his predecessor, Mike McGlinchey (who’s with the Denver Broncos), his pairing with struggling right guard Spencer Burford (who has the second-most penalty yards of any NFL offensive lineman) has meant inefficient play from the right side of the 49ers’ line.
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The 49ers overcame this weakness through the first five games by running heavily to the left side, where a healthy Williams led the NFL in run-block grade over that stretch. He was essentially a cheat code for Shanahan before injuring his ankle in Week 6. Although Jaylon Moore has been a solid replacement — he’s allowed only three pressures over 73 pass-blocking snaps — the 49ers’ rushing efficiency has suffered a clear per-play dip without Williams’ elite presence.
Samuel’s absence has also been a clear part of that regression because his physical running style and adaptable pairing with McCaffrey strains opposing defensive alignments. And though there’s less clarity on the timing of Williams’ recovery, Samuel signaled Thursday that a return from the hairline fracture in his shoulder might be imminent.
“I’m ready to go,” Samuel said during an appearance on “Up & Adams.”
Updating our chart through week 8 on WR separation and post throw grade (Catchpoint+YAC) pic.twitter.com/kD1NUdlLAm
— Jrfortgang (@throwthedamball) November 1, 2023
All three of the 49ers’ top receivers — Brandon Aiyuk, Samuel and Jauan Jennings — are in the desired upper-right corner of that graph, which measures PFF’s separation grades (x-axis) and catch point/YAC grades (y-axis). Aiyuk is an outlier on the far right. He’s also ranked No. 2 behind only Miami’s Tyreek Hill in PFF’s measure of yards per route run, an overarching benchmark for receiver efficiency.
The 49ers’ positioning on that graph is impressive, and it doesn’t even include all of their skill position assets because the stable also includes McCaffrey and Kittle — both of whom have been productive catching the ball this season.
There is no shortage of explosive talent here, from the quarterback to his targets. And that’s why the 49ers have been the third-best offense in football through eight games, even despite their relative struggles over the most recent three.
It’ll be about binding production together over the back half. Purdy’s responsibilities are well defined in this regard, but that’s a task that begins up front, where the line looks forward to Williams’ return so it can return to its early-season road-grading efficiency on the ground. Of course, accomplishing that over the long run will also require Williams to stay healthy through the season’s most important stretch.
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They’re loaded with an enviable amount of offensive talent, making availability the key variable to their success as the intensity of this journey grows.
(Top photo of Brock Purdy and Trent Williams: Harry How / Getty Images)
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