As the Jacksonville Jaguars developed into one of the best defenses in the NFL in 2017, Seattle Seahawks fans grew increasingly wary of this road matchup Sunday. And for good reason: Seattle’s offensive line struggled to protect Russell Wilson much of the early year while the Jaguars bring Calais Campbell and Yannick Ngakoue leading a group that has 45 total sacks already on the season.
Jacksonville’s side, which leads the league in pass defense DVOA, has such a combination of coverage excellence and pass rush aggressiveness that it seems reminiscent of the Seahawks group that also topped Football Outsiders’ defense score in 2013. There’s also a link: Todd Wash, the Jaguars defensive coordinator, was Seattle’s defensive line coach in 2011 and 2012 and came to Jacksonville along with former head coach Gus Bradley to operate Pete Carroll’s scheme.
So how good are these Jaguars? Clearly they don’t command a label as one of the greatest units ever, without any postseason success or anything like the consistency the Seahawks achieved for a half-decade. But that doesn’t mean we can’t put their numbers up against the peak defensive dominance in Seattle.
I already mentioned sack figures and DVOA, so let’s start there. Back in ’13, the Seahawks only managed 44 sacks the whole year (the Carolina Panthers met Jacksonville’s 2017 pace with 60) but Seattle made 28 interceptions, pacing the league with 39 turnovers—tied for most with the 2015 Panthers that any team has done since. The Jags rank second in interceptions and takeaways behind this year’s Baltimore Ravens, and don’t seem poised to outdo the Seahawks’ takeaway totals. Jacksonville has also traded places with the Ravens as the defensive DVOA leader (Baltimore currently ranks no. 1 overall), while Seattle dominated 2013 finishing nearly 10 percentage points ahead of the nearest challenger. But the Jaguars’ pass defense actually has a higher absolute score right now than the Seahawks produced in 2013.
However, several recent teams can claim superior DVOA figures including the 2015 Denver Broncos. Where Seattle’s particular recipe for generating sacks and interceptions, preventing touchdowns and forcing checkdown outlets truly shines historically is in ANY/A, which literally measures all these things. The Seahawks’ 3.2 adjusted net yards per pass attempt allowed didn’t just lead the league by more than a yard in 2013, it stands as the best mark relative to league average since the 2002 Tampa Bay Buccaneers—and the fourth-best such differential since 1950.
Jacksonville gives up a tremendously low 3.4 ANY/A, the best any team has done since Seattle both absolutely and relatively (the 2015 Broncos didn’t even lead the NFL that year—Carolina did at 4.5), and thanks to defenses like the Jaguars and Ravens the league average is actually down this year as well after rising incrementally each season since 2013. Here you can see the figure accumulated in context of the number of plays each defense faced, expressed by Charles McDonald as ANY/A value:
forgot to update for sunday's games. jacksonville is now 9th in defensive ANY/A value since 1982. pic.twitter.com/j8OItDj90B— charles mcdonald (@FourVerts) December 8, 2017
(The 2008 Steelers had a worse ANY/A differential than 2013 Seattle did, because the league average was closer to five yards per attempt, but also faced more passing plays so the total adds up to greater value.)
So the Jags look like a great pass defense—just not as great a unit as their Seahawks predecessors.
However great Jacksonville is on the corners with Jalen Ramsey and A.J. Bouye, it’s also worth pointing out that Barry Church and Tashaun Gipson don’t exactly bring to mind the ferocity of Kam Chancellor and Earl Thomas—especially from 2013. That’s one of the reasons the Jaguars haven’t been a spectacular run-stopping team in 2017.
Although that Seattle group wasn’t as well known for its stoutness up front as its more famous pass defense, it was still ranked seventh against rushing by DVOA. By contrast, even though the Jaguars have been excellent versus the pass all year and that supports their high overall rating, they were the worst defense against the run as recently as week seven.
Jacksonville then worked the telephones on its bye and took advantage of a Buffalo Bills organization whose 5-2 start was not in its tanking plans to add Marcell Dareus for just a sixth round pick. Since joining the Jags, Dareus transformed that defense into a much more complete unit.
Consider these splits: In its first seven games, not counting kneeldowns, Jacksonville allowed fully 5.3 yards per rush; in the next five games it gave up 3.6. That suggests Dareus knocked 1.7 yards off opponents’ average! With Dareus lined up at nose tackle between the guard and center, or next to Malik Jackson at the 3-technique, oppenents converted first downs on runs less often (20.5 percent from 23.9 percent), fumbled four times in five games after fumbling just twice in the previous seven, and scored just one rushing touchdown compared to five before Dareus.
Dareus makes the Jaguars even more scary than before for the Seahawks and their frequent struggles to run the football. And Dareus may be a key component as Jacksonville tries to establish a longer legacy in its first postseason run since 2007. But as far as judging this Jaguars squad historically, they will have to live with its bad run splits on the permanent record because as Seattle learned after losing Earl Thomas in 2016 undermined its continuity among the top pass defense statistics, you don’t get to pick and choose which games count in the overall chronicles.