Run defense is overrated. More accurately, great run defense, over the course of an NFL season, doesn’t correlate to winning football games.
That’s not to say run defense doesn’t matter at all, because of course it does. But, all things being equal, and as you’ll notice in the numbers through the above link, it’s pass defense — specifically defensive passer rating — that correlates to victory.
Run defense is selectively important. Because the closest thing the Saints have to a base defense is a nickel, no one should be surprised that the team allows a relatively high number of yards per rush attempt.
But when the Saints specifically choose to stop the run, they can. Knowing the 49ers would try to exploit what they saw as a Saints vulnerability, Rob Ryan deployed a new defensive front against them. Mike Triplett, in a great recap over at ESPN, described that front as a 3-5 defense. It’s more accurately described as a 4-4, but that’s just a quibble.
Rob Ryan’s 4-4 Front
First, notice the location of Junior Galette, on the right side of the image. Technically listed as a linebacker, Galette has played plenty of defensive end this year, and that’s what he’s doing here. We know Galette is playing defensive end because he has his hands on the ground, but even more importantly because of his location at 7 technique, or right outside the offensive tackle. He is a fourth down lineman.
Second, look at Parys Haralson, lined up opposite Galette on the left side of the image. He’s playing strong side linebacker, and we know this because, yes, he’s standing up, but also because he’s lined up outside the tight end, Vernon Davis, not outside the tackle. It’s an admittedly-tiny distinction, but, then, most of these fancy football things are just tiny distinctions.
Four linemen, including Galette; four linebackers, including Haralson: 4-4 defense.
Finally, Cameron Jordan is lined up as a 4 technique defensive end, directly over the left tackle; Brodrick Bunkley is lined up as a 0 technique nose tackle, directly over the center; and Akiem Hicks is lined up as a 3 technique defensive tackle.
Now let’s put this thing in motion.
The 49ers run a sweep left, pulling guard Mike Iupati out ahead of Frank Gore. The Saints do everything right. They swarm down towards Gore, taking up blockers and using the numbers advantage their formation gives them to control the gaps.
Malcolm Jenkins and Ramon Humber combine to make the stop. The result is a third and long situation, forcing the 49ers to pass into a Saints dime defense and causing the first of many San Francisco punts.
The 4-4/3-5 Thing Against the Pass
The 49ers aren’t stupid. Rather than run into an eight man front every first down, they did the natural thing and began to pass against it.
Here they are preparing to pass against the 4-4/3-5 on a first down in the second quarter:
The interesting thing here is that, probably because San Francisco has overloaded his side, Galette is lined up in the 9 technique spot, basically mirrored across from Haralson. His hands are still down, and the 9 technique defensive end — the “wide nine” defense — is totally a thing, but aside from that there’s really not much of a difference between Galette as linebacker and Galette as defensive end.1
You can call this a 4-4. Mike Triplett can call it a 3-5. The guy you beat in fantasy football last week can even call it a 5-3 if he wants. Everybody would sort of be right.
Anyway, here’s what happened when the 49ers tried to pass against the apparent anti-run defense:
At the snap, the Saints quickly diagnose the play action fake and drop into a three deep zone coverage — both cornerbacks and a single deep safety covering deep, linebackers sliding over to cover the flats.
The positioning of Ramon Humber, the topmost linebacker before the snap, is reason to speculate that, maybe, Kenny Vaccaro would have been the additional linebacker in this formation if he had been available. That’s something we’ll watch for when Vaccaro returns. Regardless, Humber does a great job here, and Keenan Lewis does an even better job, quickly closing on the ball and breaking up the pass.
A closer look at this game really drives home one point: The 49ers are extremely fortunate the Saints turned the football over three times. They were unable to generate any meaningful offense against Rob Ryan’s defense.
Without those lucky breaks, San Francisco would have lost by several scores.