The first quarter of the 2020 NFL season is complete, and Jacksonville sits at third place in the AFC South with a 1-3 record. The offense has been a pleasant surprise, as it ranks 13th in yards per play and has scored 24-plus points in three of four games, but the defense, which ranks 28th in yards per play allowed, is holding the team back -- especially the secondary.
Last year, George Chahrouri and Eric Eager of Pro Football Focus published an article on the relationship between pass rush and pass coverage. Their data study found that pass coverage is more indicative of team defensive success than pass rush.
"The correlation between team-level coverage grades and EPA [Expected Points Added] allowed per pass play during that season is roughly -0.69. EPA correlates with pass rush at a rate of roughly -0.23,” Chahrouri and Eager wrote. “Coverage grades both explain and predict defensive success better than pass rush.”
In theory, it makes sense that pass coverage would matter more than the pass rush. It doesn’t matter how dominant a pass rush is if the opposing quarterback is able to get the ball out quickly and effectively against a weaker secondary. Chahrouri and Eager noted this in a follow-up article:
“The strength of a team’s pass rush is (theoretically) known a priori through game planning, so an opponent usually has the balance of the week’s preparation to scheme quicker throws, and quicker throws are every bit as valuable (if not more valuable) than longer-developing throws, especially when they are intentional. This is why, when one digs into the data deeper to see how to play success is predicted by opponent pass rushing and coverage, coverage abates play success at a much higher rate than pass rush, with or without adjusting for contextual variables.”
Coverage doesn’t necessarily have to be elite in order for the pass rush to get home, or even as good as the pass rush in some cases. But a liable secondary can make any pass rush seemingly pointless.
Enter: the Jacksonville Jaguars.
Jacksonville has allotted an enormous amount of resources to its defensive line in recent years: it has used four of its past seven first-round selections on defensive linemen (including three in the past three years) and ranked top-seven in positional spending on the defensive line from 2014-2019 (per Spotrac).
Yet, it’s clear that Jacksonville’s defense has only performed as well as its secondary would let it. Since current defensive coordinator Todd Wash was hired in 2016, the Jaguars have clearly relied on the talent (or lack thereof) of the back of its defense.
Data courtesy of Pro Football Focus
The timeline is obvious: with the additions of Jalen Ramsey and Tashaun Gipson in the secondary, Jacksonville’s Pro Football Focus defensive grade jumped from 30th in 2015 to 14th in 2016, and with the additions of A.J. Bouye and Barry Church to the secondary the following year, the Jaguars had the best defense in the league. Remember, Jacksonville ranked top-seven in defensive line spending in 2014 and 2015, but it wasn’t until the assembly of the secondary that the defense ascended to elite status.
In 2019, without Ramsey and Gipson, Jacksonville’s defense took a hit. Now, in 2020, without Bouye, Church, and the rest of that historic 2017 defense save for Myles Jack and Abry Jones, the Jaguars rank 20th in PFF defensive grade and are allowing the fifth-most yards per play in the league.
The play of the secondary has clearly been on a sharp decline in the past two seasons. The defensive line’s performance has also declined, but not as much as one might think. Jacksonville currently has a 23.2% pressure rate (per Pro Football Reference), 14th-best in the league, and it ranked sixth-best in 2019 with a 25.8% pressure rate.
But without talented players in the back of the defense to make opposing quarterbacks hold onto the ball for longer, the Jaguars aren’t getting home, as it ranks 31st in sacks this season with four. It’s 3.1% sack rate is nearly half of the league average of 6.0%.
This season, Jacksonville ranks 19th in ESPN’s team pass rush win rate metric, which measures how often team defenders are able to beat their blocks within 2.5 seconds. This metric is valuable because it separates pass rushing ability from the tendencies of the quarterback, as quarterbacks are typically responsible for the sacks they take, mostly by holding onto the ball for too long.
It’s also worth noting that Jacksonville’s opponents rank ninth, 16th, 31st and 25th in pass block win rate, so Jacksonville’s lack of sacks isn’t simply a result of a gauntlet of great opposing offensive lines.
So, Jacksonville ranks 19th in pass rush win rate, 14th in pressure rate but nearly last in sacks this season and it’s obvious that its defensive backs are a major reason why.
Data courtesy of Pro Football Focus
The Jaguars’ secondary is clearly unsatisfactory. Its best player so far this season is second-year undrafted free agent Andrew Wingard, who has been adequate in coverage, but the other members of Jacksonville’s secondary are clearly subpar.
First-round rookie C.J. Henderson had a nice debut against Indianapolis in Week 1 but has struggled since then (though it’s fair to expect his performances to improve as he continues to gain experience), while veterans D.J. Hayden, Tre Herndon and Josh Jones have offered little hope against opposing receivers.
As a result of its vulnerable defensive backs, opposing quarterbacks have fared quite easily against the Jaguars. The four quarterbacks who have faced Jacksonville thus far -- Philip Rivers, Ryan Tannehill, Ryan Fitzpatrick and Joe Burrow -- have had a combined expected completion percentage (ECP) of 65.1% against the Jaguars, per Next Gen Stats. For reference, Sam Darnold ranks 17th out of 36 qualifying quarterbacks with an ECP of 64.9%- so Jacksonville is forcing quarterbacks to throw balls with an average expected completion percentage.
However, opposing quarterbacks have connected 77.0% of their throws, resulting in a 11.9% completion percentage over expected (CPOE). For reference, no quarterback has reached a 9% CPOE in Next Gen Stats’ database (since 2016).
The four quarterbacks the Jaguars have faced all have a CPOE of at least 7.7% against Jacksonville, and a CPOE of just 2.4% against all other opponents. For reference, Derek Carr ranks third among 36 qualifying quarterbacks with a CPOE of 7.4%, and Teddy Bridgewater ranks 18th with a CPOE of 2.4%- so opposing quarterbacks have played like an average quarterback against other teams but like a top-three quarterback against Jacksonville in terms of ability to complete passes.
Jacksonville’s 77% completion percentage allowed is the most by a team... ever. Before this season, only nine teams had allowed a completion percentage of at least 70% in NFL history. Jacksonville’s 77% completion percentage allowed would easily surpass the previous record of 72.7% held by the 2016 Detroit Lions. And again, Jacksonville isn’t simply allowing a lot of easy throws: its average depth of target against is 8.1, 19th-highest in the league.
By both standard and advanced metrics, the Jaguars are allowing far more passes to be completed than expected. That’s undoubtedly a sign of a porous secondary.
What does all of this mean?
To summarize, just about every metric available indicates that the 2020 Jaguars have an average pass rush but poor pass coverage. The secondary is simply not performing well enough to give the pass rush enough time to reach opposing quarterbacks consistently, and as a result, the team ranks second-to-last in sacks so far this season.
Just four games of data isn’t an ideal sample size, but the numbers are so skewed against the Jaguars secondary that it’s difficult to reasonably come to a different conclusion. And as highlighted earlier, Jacksonville’s team history in recent years, not just recent weeks, suggests that as Pro Football Focus advocated, the play of its secondary has had a larger impact on its overall defensive performance than the play of its defensive line.
This information doesn’t help the Jaguars now but it provides a blueprint for the future. Smart organizations like Baltimore, Buffalo and New England have built their teams from back-to-front, pouring resources into their secondaries before their front sevens, and have had great recent defensive success due to successful roster construction and excellent coaching. Jacksonville possesses neither of those tools at the moment but that could change as soon as next offseason.
Whoever continues Jacksonville’s rebuild, whether or not it’s the same people in the building as right now, should keep in mind the significance that coverage has on defensive performance.