clock menu more-arrow no yes

Filed under:

Controversy boils around Aaron Donald’s run defense

Analytics twitter is starting to eat itself

Chicago Bears v Los Angeles Rams Photo by Jayne Kamin-Oncea/Getty Images

On Tuesday morning, ESPN’s Seth Walder posted his findings with a new metric he’s proud of called Run Stop Win Rate. One can assume it has similar intentions as ESPN’s Pass Rush Win Rate, a metric that Aaron Donald has dominated since entering the league in 2014, but for run defense. Walder isn’t as enthusiastic about Donald’s run defense, calling it “just average” based on his RSWR metric.

As expected, calling Aaron Donald “just average” at anything immediately brought an influx of internet disagree-ers.

ESPN’s Brian Burke posted their explanation of RSWR and Run Block Win Rate earlier on Tuesday.

The running game is all about position and angles, and so are these metrics. First, each block is identified — that’s the easy part. Next, our system determines whether the defender was able to defeat the block. It does this by using a large set of rules based on relative distance to the runner, relative velocity to the runner and many other more complicated measures. A defender doesn’t have to make the tackle to win his block. He can penetrate the backfield to cause a disruption, contain the runner behind the line of scrimmage, or squarely fill his assigned gap to earn a win. If a blocker allows his defender to win, he is debited with a loss.

RBWR works on the other side of the ball too, as they ranked Andrew Whitworth as having the seventh-best rate for offensive tackles in 2019. But defensively, Donald apparently lagged behind other interior defensive linemen. At least, according to ESPN.

But the more we watched Donald’s play, the more we came to the conclusion that the model was picking up on something. The plays marked as losses were losses, and Donald was not winning on run plays at an exceptional rate. According to the RSWR model, winning is possible by a defender:

- Beating his blocker such that it puts him in better position to stop the runner or ...

- Disrupting the pocket/running lane by pushing his blocker significantly backwards or ...

- Containing the runner, even if blocked, such that he must adjust his running lane or ...

- Recording a tackle within three yards of the line of scrimmage.

The results for Burke were that Donald had a RSWR of 29%, which was below the interior line average of 30% by one point. They measured Denver Broncos nose tackle Mike Purcell as ranking first in the league at the position with his mark of 40%. Burke and Walder also say that teams were not afraid to run right at Donald, that he ranked 130th out of 158 defensive linemen in percentage of run plays where he recorded a tackle and that opposing teams had roughly the same success rushing the ball whether he was on the field or not.

Of course, ESPN expected there to be controversy around their Donald findings as they build their entire story around it. They knew they’d be ridiculed, so they attempted to not only get ahead of the ridicule, but to accept it because Donald’s low score is the only reason people are talking about Burke’s model today.

And people certainly are talking about it.

And of course, nobody was happier to take the popular side of an argument more than PFF.

The Rams host the Dallas Cowboys on Sunday night and somehow it seems that now people might be paying less attention to how many sacks Donald gets and more attention to how many yards Ezekiel Elliott finishes with. I suspect Donald will be a quality player on the field in all instances.