49ers film room: Robert Saleh’s quarter’s coverage scheme
Today we look at the basic structure of quarters coverage within Robert Saleh's defensive scheme.
It is no secret that the 49ers defensive coordinator search ended with them reuniting with their former defensive coordinator Robert Saleh. Saleh left in 2021 to be the New York Jets head coach where he was tasked with changing the culture and rebuilding the franchise in the mold of the 49ers.
That didn’t quite work out, and after 3.5 seasons and a 20-36 head coaching record, the Jets parted ways with Saleh in October of the 2024 season. In his time with the Jets, the offense never got off the ground and he was forced into a quarterback carousel that saw starts from quarterbacks Zach Wilson, Mike White, Joe Flacco, Trevor Siemian, Tim Boyle, and…Aaron Rodgers.
The last one there…it’s not at all clear how onboard Saleh was with Rodgers coming to the Jets but the turnaround they envisioned never materialized with Rodgers suffering a season-ending injury four snaps into the 2023 season and never really finding a rhythm in 2024 as he recovered from injury and tried to find his footing again. Publicly available information suggests the two were great friends. It’s anyone’s guess and no one trusts Rodgers anyways.
Anyways, despite the offensive struggles, the Jets always fielded a top defense with Saleh, a pattern that followed him from the 49ers. Apart from 2021, where the Jets were last in both DVOA and EPA/play, Saleh fielded a top 6 defense in 2022 and 2023. In 2022, the Jets were 6th DVOA and and 6th in EPA/play and 2023, they were 3rd in DVOA and 3rd in EPA/play.
In 2024, through the first 5 weeks, the Jets were 6th in EPA/play and 12th in DVOA. Saleh was fired after week 5, and from there, the defense got worse in efficiency, finishing the 2024 season 21st in EPA/play and 20th in DVOA.
The defining feature of the Saleh defense since 2019 is a dramatic shift to a more quarters-based coverage scheme than he first intended on running with the 49ers in 2017.
In 2017 and 2018, their cover-4/quarters usage was just north of 4%. In 2019, that shot up to 22.2% and 27.6% in 2020 across all pass coverage snaps. Those were also the best years of efficiency for the 49ers under Saleh too. It would be easy to say the addition of Nick Bosa in 2019 helped push them into this realm but Bosa missed nearly all of 2020 and the defense lost little efficiency.
Under Saleh, the Jets peak was 28.4% in 2022 and 23% in 2023 of snaps spent in quarters coverage with a noticeable decline in 2024 after Saleh departed after week six, combined with the fact that the defense did not have a nickel good enough to play 75% of their snaps sub package defense. Playing around 60% in nickel, the usage of base rose to 40% and the primary coverage in base is single high cover-3.
With the 49ers again, it figures to be a prominent feature of the defense now that Saleh is back and with Deommodore Lenoir in the slot.
So what is quarters coverage?
Quarters or cover 4 is a four-deep, three-under zone defense that uses man-to-man principles (pattern matching) while creating opportunities for both the free and strong safety to double (or “bracket”) the No. 1 wide receivers.
There are two main ways to play quarters coverage: man-match and zone-match.
Man-Match
Man-match quarters, cover-7 as it is referred to in the Nick Saban lineage, is a particular man coverage assignment until that receiver does something that triggers the defender to become man-to-man with another receiver.
In man-match, the corners play man to man on the outside receivers with leverage depending on the divider (outside or inside depending on receiver alignment inside the numbers or outside the numbers) and play aggressive on anything out breaking 10 yards or deeper.
Anything breaking inside before a depth of 10 yards will be handled by the flat defenders, who then match the receiver man to man. For example, if a corner has the #1 receiver on any vertical route. If that receiver does anything else, like run a shallow cross or short hitch, then the corner will find the next vertical threat or zone off.
Zone-Match
Zone-match is a bit different. In zone-match, the defenders are dropping to an area while visioning the QB top-down. The rules change such that when a receiver enters the defender’s zone, the defender will take him man-to-man. Defenders have a “no cover zone” in the flats where they will not take a player man-to-man until the ball is thrown.
In zone-match, the defenders will still play the same man coverage principles, but will do so with eyes on the quarterback, especially the safeties as they cap vertical routes over the top. An example of zone matching would be when a WILL linebacker drops to the hook zone and the final #3 receiver runs up through it. The WILL now “ROBOT’s” the crosser and runs man to man with the receiver.
The safeties will either bracket the outside receiver with the corner if the No. 2 inside receiver runs any shallow crosser or out route. If the inside receiver gets vertical, then the safeties will cover man to man on seam or deep cross, dig or hook route.
49ers quarters defense
Under Saleh, when the 49ers defense plays quarters, they will exclusively be a zone-match quarters defense, letting their best players read the quarterback’s eyes.
Here are the base quarters zone versus a 12 personnel 2x2 formation. This is as basic as it gets for quarters assignments with the safeties playing anything vertical, the overhang nickel and WILL linebacker playing the flats, and the MIKE linebacker playing the middle of the field walling off anything over the middle.
Against the Browns here in the 2023 preseason Hall of Fame game, the offense comes out in a 12 personnel formation (one running back, two tight ends) running a variation of a “hank” (curl/flat) play action concept with a corner-stop route on the right, a vertical go route on the left, and two chip flats on both sides.
The safeties, WILL linebacker, and nickel defenders are reading the release of the inside tight ends to see if any push vertical or out.
The moment they chip, the safeties automatically know there is no vertical threat and can get their eyes on the receivers pushing vertical while the overhang defenders push to the flat with the chip release tight ends.
The nickel is playing “curl over flat” and gains depth while widening to the sideline so that he’s in a position to make the tackle. He unfortunately ends up missing the tackle but you can see how rallying is a central focus of quarters defense.
The quarterback ends up making the wrong read. He should be throwing away from the nickel rotation, especially with the WILL so far inside and unable to really squeeze a throwing window to the left or keep up with the flat.
In part two, we’ll look at some quarters variations in the evolution of the Saleh scheme.