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How the 49ers’ quarterbacks affected the offensive line play in 2020

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Photo by Norm Hall/Getty Images

As we’ve focused on quarterbacks for the past month, the San Francisco 49ers offensive line have found their way into these conversations. Oftentimes, negatively, thanks to ESPN’s stat called “pass block win rate.”

Here’s how ESPN describes PBWR, the metric:

Our pass rush win rate metric tells us how often a pass-rusher is able to beat his block within 2.5 seconds.

The 49ers ranked 22nd in 2020 at 54% in PBWR. They were worse in 2019 with a 45% win-rate, but the team ranked higher as the Niners finished 13th.

The stat sounds good in theory, but it lacks the nuance and context necessary to be reliable. PBWR doesn’t factor in blitzing or double teams, both of which are essential factors when talking about line play on either side of the ball. You could argue that the offensive line works to have a double team on more plays than not. Add in the lack of blitzing, and PBWR effectively ignores a good portion of plays during a game.

Another issue with the statistic is that each pass is treated the same. If you run a play-action pass in attempts to throw the ball down the field on a seven-step drop, that’s treated no differently than a three-step drop where you’re throwing a slant. That’s a problem.

When you can poke that many holes into a statistic, it’s time to stop using the said statistic.

For no particular reason, let’s compare the 49ers' offensive line to Lions this past season. There isn’t one end-all-be-all statistic that we should use for any position. For offensive line play, it’s nearly impossible to quantify.

The common offensive line metrics

We could use PFF grades, but those are subjective and generally only are affected when a player is involved in the play. PFF ranked offensive lines around the NFL earlier in January, where they had San Francisco ranked No. 9 compared to the Lions at No. 13.

Football Outsiders has adjusted sack rate, but there are plenty of occasions during a game where the quarterback is responsible for taking a sack. In this metric, Detroit ranked 21st in adjusted sack rate while San Francsico finished ninth.

Using PFF’s data, Stafford was responsible for nine of the Lions' 42 sacks this past season. Four (three came in one game) of their 32 QB hits, and four of Detroit’s 109 pressures this season. Even then, that doesn’t account for how often Stafford had to deal with an unblocked rusher.

Between Jimmy Garoppolo, Nick Mullens, and C.J. Beathard, they were responsible for eight of the team’s 35 sacks, seven of the 56 QB hits, and five of the 111 pressures, per PFF.

There are plenty of examples where a free runner doesn’t faze Stafford. Here are examples of Stafford helping out his offensive line:

Too often during the past couple of seasons, we’ve seen 49ers quarterbacks crumble at the sight of pressure. It hasn’t been pretty when the situation isn’t perfect.

Saying, “quarterback X will struggle behind this offensive line” because the current quarterbacks did ignores what other quarterbacks have done in the past. We’ll talk more about the specific quarterback, especially if it’s Stafford, and how they deal with the pressure once a move is announced.

A wise man once told me it’s best to judge a quarterback when they’re playing in a situation where they’re uncomfortable, and the bullets are flying. A two-minute drill is a great example, as is when a quarterback is pressured.

Pro Football Reference keeps track of average time in the pocket, though that number could vary based on the offense. Both the Lions and the 49ers' offensive lines gave their quarterbacks 2.4 seconds on average in the pocket. The league-high was 2.6, which was the average for eight teams. Six other teams averaged 2.5, while the majority of the league, 13 teams, in this case, averaged 2.4 seconds to throw. Pittsburgh was listed as the lowest with 2.1 seconds to throw.

When referencing pressure numbers, like PBWR, it’s important to factor in how many times a team was blitzed. If a team knows a quarterback struggles under pressure, they're going to be blitzed more. It felt that that was the case for San Francisco this season as Beathard and Mullens lack experience.

Knowing where to go with the football comes with experience and game reps, both of which the Niners quarterbacks lack. Detroit was blitzed 194 times compared to the Niners 192. San Francisco’s offensive line allowed three more hurries but 34 more quarterback hits. That’s a quarterback problem.

The best quarterbacks don’t just know where to go with the football; they know where all of the routes are. How often did we see the 49ers quarterback's head spinning in the backfield this past season?

Even with the arm strength of a middle-schooler, Drew Brees finished 10th in the NFL in EPA per play because if routes one or two weren’t open, you’d see him flip all the way around and throw a five-yard pass. That’s because Brees has the correct process and knows where all of his receivers are.

I get the same feeling when I watch Detroit. The same thing cannot be said for San Francisco, which is why the difference in QB hits between the two is notable and matches up with what you see when you watch both teams play. An experienced quarterback shaves off at least ten of San Francisco’s quarterback hits from this past season.

The issues with blown blocks

Back to the offensive line, Sports Info Solutions charts “blown blocks,” which is exactly what it sounds like. If an offensive lineman gets beaten, it’s a blown block. The stat is still subjective to a degree, but it’s as straightforward as it gets and easy to understand.

Quarterbacks run into sacks and hold the ball too long. That’s not changing any time soon. Stafford does it plenty of times, and pretending like he’s prime Peyton Manning isn’t fair, or is it accurate. Stafford’s an above-average quarterback, but he’s not “elite.”

As much as I love blown blocks, even that stat is impacted by the quarterback. If a guy gets beaten in pass protection, and you’re charting objectively, you’re going to mark him down for a blown block, even if the ghost of Beathard failed to pull the trigger.

Here’s a look at each team’s starting offensive line’s blown block percentage and PFF pass-blocking grade. Remember, both teams had the same average time to throw in the pocket.

My takeaway from the data above follows the theme of the article. Look at the difference between Tomlinson’s blown block percentage and Aboushi’s. Then take a peek at their PFF grade.

It matches the video from Stafford above, and it matches with what we saw all season from the 49ers offensive line. Those 10-20 plays where the Niners quarterbacks were either unsure where to go with the ball or held onto it too long is a direct reflection of Tomlinson’s numbers.

If you ask a Lions fan how their offensive line was, they’d have the same answer as most fans of their teams would: it was putrid. One fan told me this year was the second-best line that Stafford has had during his entire career. That’s jaw-dropping, as they were noticeably worse than San Francisco’s in the handful of games that I’ve watched.


I’m not arguing that the 49ers' offensive line was the same as the Packers or the Saints. I’m arguing that if you get a quarterback who is closer to Green Bay’s and New Orlean’s caliber, the deficiencies of the offensive line won’t stick out like a Jim Harbaugh outburst on the sideline.

When going through whether a quarterback is an upgrade or not, we have to talk about how he affects every aspect of the game. It’s not just deep passing or turnover rate. It includes everything from eluding pass rushers to getting the ball out and avoiding six-yard losses.

Again, if Stafford lands in San Francisco, he’s not going to cure all of the 49ers' issues magically, and expecting him to do so is setting yourself up for disappointment. What Stafford and an experienced quarterback do offer is protection for your five guys up front.

Look at the offensive lines in the Super Bowl. Tampa Bay is on their backup right guard, while Kansas City is starting a pair of fourth-stringers on the right side of the line and two backups on the left side. Every team deals with injuries, and offensive line play is at an all-time low.

A quicker decision-maker under center for the Niners will change the perception of the offensive line. As would a quarterback who wasn’t uncomfortable once he had to move off his initial spot. If the Stafford rumors are correct, we’ll find out soon enough.