Seahawks front four need better backfield penetration to stop Todd Gurley and Rams’ attack

The Los Angeles Rams went from objectively the worst offense in the NFL in 2016—dead last in both run and pass DVOA—to one of the better units through four games in 2017: Tops in scoring, second in total yards and yards per play and sixth in Football Outsiders’ efficiency. Some of the credit for that improvement goes to Jared Goff, who stepped up his performance from a dreadful rookie year to post the 10th-best QBR by dramatically cutting down his interceptions. Goff averaged one pick per start last season but has just one total in this young campaign. Thanks to Goff’s development and Sean McVay’s innovations to the scheme, L.A. has the best passing DVOA in the land right now.

The Rams’ run game is not quite so efficient, with a minus-11.6 percent rating by Football Outsiders that ranks 19th overall. But Goff and the Los Angeles passing attack get tremendous help from Todd Gurley and the Rams’ rushers anyway, who have been solid enough to take much of the load off Goff by affording McVay to call the third-lowest rate of pass attempts in the league—technically it’s the most balanced offense, with a 51-49 percent split.

In turn, this relative run success comes from Los Angeles’s upgraded offensive line. In his rookie year in St. Louis and also last season, Gurley’s runs got stuck in the backfield a remarkably high amount, which pounding probably contributed to Gurley’s sophomore decline: In 2015 Gurley owed his Rookie of the Year award mostly to his own ability to transcend that blocking and burst for 6.7 yards a pop on carries when he got beyond the line of scrimmage. That might have been unsustainable anyway, or Gurley started to break down, but by 2016 he was last in the league among qualified ball-carriers with just 4.5 yards per attempt on those plays—resulting in 216 yards less than expectation for an NFL-average starter. His open-field rank by Football Outsiders dropped from third to 30th.

The Rams went out and hired left tackle Andre Whitworth and center John Sullivan. Now, with adjusted line yards boosted from the 3.5-3.6 yard range to 4.4, Gurley is enjoying more room to run in the backfield and Richard Sherman, who has watched more of than film than I, says the holes are more open at the line of scrimmage. Gurley’s yards per carry is back over four yards overall (from 3.2 in 2016) and Ryan Keiran places Gurley fourth in the league at run production contributing to win percentage, better than formulas like DVOA or DYAR would indicate. In fact, because L.A. has been in position to run so often, Gurley is the only player in the top five of the NFL in both rushes and OrW-percentage (offensive rushing win percentage).

That makes a better case for Gurley as the NFL MVP so far than the traditional counting stats argument.

To bring this around to the Seattle Seahawks, with Seattle’s own offense expected to have trouble getting first downs with its pitiful offensive line against the Rams’ fearsome front group, it will be critical for the Seahawks to limit Gurley’s advancement when Los Angeles has the ball. The aim has to be getting Goff into third and long situations as much as possible, as Mike Chan warns.

Seattle was exceptional at doing just that to Gurley in 2016, holding Gurley to 89 yards across 33 attempts in two games. But again, that was against a different Rams offensive line, and with a different Seahawks defense. The Seahawks were the best run defense in the NFL last year in yards per carry allowed, third in rush defense DVOA, and generated the most expected points from run-stopping in the league.

In 2017, Seattle is second-worst in the league allowing 5 yards flat per rush. Part of that is skewed heavily by several long runs by the San Francisco 49ers and Tennessee Titans—the Seahawks didn’t give up any runs longer than 35 yards a year ago, and only five more than 20 yards—but Football Outsiders adjusts for those unpredictable outliers and still puts Seattle 30th in rush defense DVOA and 18th in adjusted defensive line yards. The Seahawks’ run defense has added negative value, according to expected points.

On its interior rotation, Seattle essentially swapped run-plugging nose tackle Ahtyba Rubin for a more versatile talent in Sheldon Richardson, but Richardson is supposed to be an elite run defender as well so it’s not clear what’s causing the Seahawks woes against the rush apart from missed open-field tackling. What is clear is that it is more than downfield discrepancies:

As Justis Mosqueda highlights, Seattle has generated the fourth-worst tackles for loss per rush. That means the Seahawks are not getting frequent enough penetration past their blockers. That monstrous defensive line was expected to be eating opponents’ brains in the backfield all season, but the vaunted group has only stopped nine run plays (8.7 percent of rushes) behind the line of scrimmage so far (curiously, six of them came against the boom-and-bust Titans who also maxed out with 100 yards on two other Demarco Murray rushes). Compare that to the 11.6 rate from a year ago when that slight three-percent-of-all-rushes difference generated a value score relative to league average of plus-6.0—an 11 point swing in TFL percentage value!

That difference can have huge impact on wins and losses because, as Pat Kirwan among others have studied, the difference between second and 10 or more versus second and seven or eight, or between third and seven versus (like Chan says) third and three or four, significantly alters the chances of gaining first downs, adding expected points and other factors that lead to victory. The charts in those links use old data, but the principles remain the same in today’s NFL.

Mosqueda’s parenthetical question expresses how confusing it is for Seattle to be struggling in this regard, and we may find those tackles for loss indeed regress toward a value more similar to 2016’s rate as the season moves on. However, in the short term, the Seahawks enter this matchup with highly volatile consequences extremely thin on that front rour, scrambling to add to the defensive line rotation after Cliff Avril’s and Quinton Jefferson’s injuries in the past week. Frank Clark is a powerful replacement for Avril on the edge, but when Clark started five games in 2016 during Michael Bennett’s absence Seattle’s run-stopping declined sharply, from three yards per attempt to 4.5, owing to that loss of depth.

That shifts the focus to players like Marcus Smith, an effective contributor last week but still an uncertain variable for now, as the Seahawks try to limit Gurley and control the Los Angeles Rams with their defense. While many Seattle fans spent all week worried about what havoc Aaron Donald and Robert Quinn might bring to the Seahawks backfield, the game may turn on what kind of damage the shorthanded Death Row defensive line can do to the L.A. ground game.