Seth Walder of ESPN Analytics will be writing a new fantasy football column this season using Next Gen Stats to analyze how the offensive line and opposing defensive line matchups affect running back production on a week-to-week basis. NFL player tracking, also known as Next Gen Stats, is the capture of real time location data, speed and acceleration for every player, every play on every inch of the field. Sensors throughout the stadium track tags placed on players' shoulder pads, charting individual movements within inches. A version of this column was published in the ESPN Fantasy Football magazine, on sale right now.
Austin Ekeler played the 2020 season with a disadvantage. A blocking disadvantage.
The Los Angeles Chargers finished last in 2020 among all teams in ESPN's run block win rate - a metric designed to capture a team's run blocking effectiveness using player tracking data from NFL Next Gen Stats. But we've got good news for Ekeler and his backups Justin Jackson and Joshua Kelley: all that is about to change. With the Chargers addressing their offensive line during the offseason, we're projecting them to leap all the way into the top 5 in run block win rate (RBWR) in 2021; a potential boost not only for Ekeler and Co., but their fantasy managers as well.
We've always known run blocking was important to football and fantasy football alike. But quantifying it - and then predicting it - was a challenge. The first part of that was handled in 2020 by the creation of RBWR.
As a refresher: what constitutes a run block win? If a blocker is able to prevent his man from all of the following, he earns a win:
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.
On each play, every blocker receives either a win or a loss, and the team earns a run block win rate based on the cumulative results. League average for teams in 2020 was 70.5%.
To no one's surprise: plays with better run blocking result in more yards gained.
The table above is cheating slightly, because a tackle within three yards of the line of scrimmage counts as a run block loss. But even if that criteria is removed, the same general pattern emerges.
On the team season level over the past three years we can see there's a moderate relationship between run block win rate and yards per carry. Accounting for no other factors, every percentage point increase in RBWR equates to a little over .08 in yards per carry over the course of a team's season. The correlation coefficient (r) is .38.
But what about predicting run block win rate?
To take a stab at that we built a model based on the past performance of individual players. The model is based on the projected offensive line starters for each team (Source: ESPN's Mike Clay) and those players' previous run block win rates each of the two seasons prior. For players who didn't reach a qualifying threshold, their RBWRs were regressed toward a below-average replacement value.
A linear regression of the two averages of the five starters' run block win rate from the prior season and season before produced an out-of-sample correlation coefficient of .46 on a one-year test set. In other words: we do have some ability to predict a team's run blocking!
So let's get to it: where do 2021 teams stack up in our predictions?
Dallas, Baltimore and Philadelphia lead the way while Las Vegas, Atlanta and Buffalo lag behind at the bottom of the list. But perhaps more important for drafting purposes than where a team falls on the prediction list is which teams or running backs should achieve significantly different run-blocking relative to last season. After all, fantasy is about beating expectations: if a running back is expected to receive the same level of blocking that he received last season, presumably that blocking -- good or bad -- is already baked in to his ADP.
Predicted run blocking is not some sort of panacea: What we're talking about here is a correlation of a correlation. Past run blocking correlates to some degree with future run blocking, and run blocking correlates to some degree with rushing efficiency. Which means, to me, this isn't a starting point for creating rankings but is a tool I'd consult to move players up and down a few spots.
With that in mind, let's identify some of those winners and losers off these predictions.
Winners: Ekeler, Jackson and Kelley
The aforementioned Chargers rebuild should have significant effect on their run blocking. The most important signing was center Corey Linsley, who ranked first among all centers in RBWR last season and will replace Dan Feeney, who ranked 29th at the same position. Oday Aboushi, another signing, was an above-average run blocker last year as well. Add in first-round rookie Rashawn Slater and Bryan Bulaga -- who ranked third among tackles in RBWR last season in the 10 games he played -- and there's huge run-blocking upside here, particularly because we're not even assuming strong play from Slater yet.
Of course, a healthy portion of Ekeler's value comes from the passing game which is completely separate from our focus here. But nonetheless: the Chargers' offensive line investments should set up more favorable runs for Ekeler when they do use him on the ground. Ekeler's backups have a higher ceiling as late-round fliers, too. No player with at least 100 carries last season received worse run blocking help than Kelley, as his blockers recorded just a 65% RBWR on his runs.
Winner: Clyde Edwards-Helaire
After Patrick Mahomes was on the run in the Super Bowl, Kansas City's offensive line rebuild was surely directed at giving him better pass protection. But Edwards-Helaire is going to end up a beneficiary as well. The major upgrade comes in the interior of the line, where last year center Austin Reiter and guards Nick Allegretti and Andrew Wylie ranked fourth-to-last, fourth-to-last and last in RBWR at their respective positions. New center Creed Humphrey and guards Joe Thuney and Trey Smith all project to be improvements, even though Humphrey and Smith have never taken an NFL snap. While the model assumes rookies are below average, in this case that still is an advantage over how the interior of the Chiefs' line run blocked last season.
At tackle, Orlando Brown Jr. should be a clear run-blocking upgrade over Eric Fisher -- who finished bottom 5 in RBWR last season -- as well. Altogether, it's good news for fantasy managers hoping to buy low off a disappointing Edwards-Helaire rookie campaign.
Winner: Ezekiel Elliott
Dallas topping our predicted RBWR rankings is all about the upside of this offensive line if it can stay healthy. Last year Dallas got 0, 2, and 10 games out of La'el Collins, Tyron Smith and Zack Martin, respectively. If it could get full seasons out of those three, but in particular Smith and Martin (who ranked fourth among guards last year), that would go a long way for the Dallas offense and Elliott's fantasy season.
But also, don't sleep on second-year center Tyler Biadasz. The former Wisconsin offensive lineman posted a fantastic RBWR in limited playing time (four starts) last season.
Loser: Aaron Jones
The flip side of losing offensive linemen to the Chargers is what's left in Green Bay: still some elite players in David Bakhtiari (who will start the season on the PUP list; The model isn't aware of Bakhtiari's early-season absence, so Green Bay might take an even larger step back) and Elgton Jenkins but less talent there overall. No team is expected to take a bigger step back in RBWR than Green Bay, though I'll add that I'm somewhat wary of fading the Packers offensive line considering how strongly they've ranked in the win rates in past seasons, despite some turnover.
Loser: Najee Harris
Pittsburgh had the 7th-worst run blocking unit a season ago and then lost its only two starters who were above average in RBWR at their position: Maurkice Pouncey and Alejandro Villanueva. The result is a unit predicted to be the 4th-worst at run blocking in the NFL next season, an ugly scenario for Harris to walk into.
Loser: Christian McCaffrey
The Panthers still have Taylor Moton and Matt Paradis -- top 10 in RBWR at tackle and center, respectively last season -- along their line, but likely will see a big drop in run-blocking production out of one of their guard spots. Chris Reed, who was below average in pass blocking but above average in run blocking, walked in free agency and his stead will likely be filled by former Vikings and Jets guard Pat Elflein, who was the third-worst in RBWR at the position last season.
Brian Burke contributed to this article.