The Jacksonville defense ranks 32nd in rushing yards allowed and rushing yards per carry allowed, making it the worst rushing defense in the league by either measure. Some of this is the result of the small sample size of a four-week season: Bilal Powell had a 75-yard fluke touchdown run on Sunday against the Jaguars, and backup Elijah McGuire had a 69-yard run a couple hours later that, while not fluky, is probably not going to happen every four games.

But that’s not what’s weird about the Jaguars defense.  What’s weird is that opposite the worst rushing defense in the league is the stingiest pass defense, in terms of both yards (meaningless) and ANY/A (very meaningful). The Jaguars lead the league in sacks, with 18, while ranking 3rd in passer rating (which doesn’t include sacks). So this is a really strong pass defense, at least through four games.

In theory — more on this in a minute — a team shouldn’t be really good at pass defense and really bad at rush defense, absent some extreme roster composition. And with Calais Campbell, Yannick Ngakoue, Malik Jackson, Paul Posluszny, Myles Jack, and Telvin Smith, the Jaguars front seven has more than enough talent to turn this thing around.  If I had to guess, the rush defense will improvement significantly, while the pass defense will still play like a top-10 unit the rest of the way.  In other words, this should be a really good defense, not just a really great pass defense.

The Broncos currently lead the league — by a wide margin — in rush defense. The Broncos are allowing just 2.4 yards per carry and just 50.8 rushing yards per game; the Bucs and Eagles are 2nd at 2.9 and 70.8, respectively.  This is notable because while Denver had an incredible defense in 2015, and an incredible pass defense in both 2015 and 2016, its run defense was a disaster last year. Denver ranked 1st in both pass defense and overall defensive DVOA in both 2015 and 2016, but fell from 4th in rush defense DVOA in 2015 to 21st in rush defense DVOA last season.  This year, the run defense appears to not be an issue.

I am not too surprised by that result.  Eight years ago, I wrote a two–part series explaining why the concepts of pass defense and run defense are perhaps too complicated: we should just think of defenses as defenses.  The theory — which upon a re-read today I still support — is that if a defense has had disparate results against the run or the pass, that defense can tweak its strategy to achieve equilibrium.  If your pass defense is great and your run defense is poor, there are ways to fix that: play dime and nickel less often, bring more defenders into the box, alert your to defenders to play the run first, put more run-focused defenders onto the field, etc.

We spend a lot of time, myself including, focusing on the granular aspects of NFL play. But sometimes it’s worthwhile to take a step back, too, and realize that in many ways, a defense is just a defense.