Welcome to another great day in the Summer of Spags!
When we last talked coverage, we discussed the coverage rules and permutations of 2-read pattern matching coverages. I highly recommend reading that post before we dig into today’s topic — 4-read coverages!
Known to some as Quarters — or to Nick Saban as “Box” or “Mod” — 4-read coverages share a lot of similarities with 2-read. The same idea — driving on out routes with unexpected receivers — is very important to the function of the coverage. 4-read is typically an early down or red zone coverage, and Steve Spagnuolo uses it frequently in those situations.
Where 2-read asks the boundary cornerback to drive on an out route inside of linebacker depth while the safeties to stay on top of vertical routes, 4-read makes a small tweak to flip that responsibility. The boundary cornerbacks are responsible for topping vertical routes on the boundary. Meanwhile, the apex defender — the coverage defender inside the boundary cornerback — is responsible for the first out route inside linebacker depth, and the safeties become intermediate zone players.
By putting the cornerbacks on an island against vertical routes, the safeties are not required to cover all the way to the boundary. This allows the safeties to step forward and rob routes or fill responsibilities of blitzing players. This also allows the safeties to participate in run fits, creating a late-spinning eight or nine man box against the run.
Let’s take a look at some examples to show some usage cases — and how the Kansas City Chiefs coaching staff might utilize this coverage in games.
- Cornerback (boundary): From press or man coverage, play man-to-man on all routes by the number one receiver — unless the receiver breaks inside or outside within linebacker depth. If the receiver breaks within linebacker depth, zone to deep quarter.
- Apex: Take the number one receiver if he breaks within linebacker depth, or the first player to the flat. This includes the number two (or three) receivers on a bubble screen or a running back in the flat. Align with the number two receiver so you can collide or disrupt the receiver on the way to the flat.
- Safety: Take the number two receiver’s vertical route. If number two’s route is not vertical, move to help bracket the number one receiver. Patience while reading the number two receiver is key. Since the cornerback is in man against the number one receiver, the safety can move late to help and rob routes.
Against 2x2 formations from the offense, these three players work in a triangle to cover two vertical routes and protect against bubble routes — exactly like 2-read. However, the patience by the safety allows for a delayed reaction to any route distribution due to play-action passes.
It can also help with blitzes from the apex defender, as this play shows.
4-read coverage is an early down coverage call that requires the boundary CB to "top" any vertical route from the #1 WR and moves the safeties into an intermediate zone. The apexes are responsible for anything out in the first 5 yards, unlike 2-read where that was the CB's job. pic.twitter.com/Yx5mvfwKqt— Craig Stout (@barleyhop) July 13, 2019
Against a 2x2 formation with 11 personnel (one running back, one tight end, and three wide receivers), the defense is in the nickel. The offense runs two out routes within linebacker depth along with two deeper in-breaking routes on the boundary and a curl from the tight end. The call is for the nickel cornerback to blitz from the field, moving the field safety down to the slot. He is still responsible for anything vertical on the number two receiver and will break on the first out to his side of the field.
The defense shows blitz from the MIKE linebacker, and the late rotation from the safety has the quarterback looking to get the ball out quickly to the flat. In man coverage, the WILL linebacker — the apex to the boundary — would be stuck on the curl from the tight end. The running back in the flat would be tracked by the MIKE linebacker, having to cross through traffic and arriving late to the back. It’s a good man blitz-beating play. Instead, the defense is in 4-read and that allows the WILL linebacker to drive on the flat while passing the tight end to the MIKE as a hook defender. Instead of a big play, the result is a minimal gain on first down.
It’s worth noting that the boundary safety starts his backpedal a little early on this play, leaving a wide space between the apex and the safety. He’s correct in getting over the top of the route once the tight end pulls up on the curl, but the initial backpedal leaves a little more space than desired between the second and third levels of the defense.
Flood concepts are great ways to beat match coverages, but a well-executed match coverage can force the QB deep into his progressions. LB colliding and carrying to better coverage players and asking for coverage in the flat helps to minimize the effect of poor coverage defenders. pic.twitter.com/6YzxXTTHrG— Craig Stout (@barleyhop) July 13, 2019
Here we see Spagnuolo operating out of his base defense against 12 personnel (one running back, two tight ends, and two wide receivers) against a 3x1 formation. Much like 2-read, Spagnuolo operates out of a box — four defenders over three receivers. The apex is still responsible for the first route in the flat, but the MIKE linebacker now becomes more involved as a “collision and carry” player from these tight splits. His responsibility is to “match three to two,” meaning he reads the number three receiver to see if he runs a vertical route stem — and if not, he reads the number two receiver for the same.
The offense runs a flood concept against this match coverage — a very good idea, as that can pull multiple coverage defenders away from a section of the field as the defenders match the route distributions. However, flood concepts do take time to develop — a risky concept against a blitz-happy defense like Spagnuolo’s.
As before, the cornerbacks are responsible for topping the routes on the outside or zoning off if the receiver breaks inside linebacker depth. The safety to the play strength becomes a fit-support player and reduces the gap that the MIKE linebacker has to carry a receiver vertically before taking that receiver in man coverage.
The SAM linebacker is tasked with defending the flat in this 4-read distribution against a backup tight end. He zones over the flat, taking away the throw, then moves toward the crosser as the quarterback moves through his progressions. The crosser is open for a short gain — again, flood concepts can beat match coverages — but the route concept has him looking for the ball later in the snap and the result is a sack.
There are many ways that this offensive route combination could spell doom for the defense. In a static Cover 2 — or even potentially a 2-read scenario for some coordinators — the tight end in the flat would pull the boundary cornerback up and leave the safety arriving late to the number one receiver, thereby leaving the MIKE or SAM with the responsibility to cover the number two receiver down the field. Instead, a well executed 4-read call helps force the quarterback deep into his progressions and gives a four-man pass rush time to net a sack on an early down.
This is yet another very abridged version of a coverage call in Steve Spagnuolo’s arsenal. Permutations of this call will show up on different distances, receiver splits, positions on the field, and — most obviously — game situations.
However, the key component in 4-read is the ability for the safeties to step up and be able to fit into intermediate zones, allowing them to offer fit support in the run game off the linebackers and defensive line in front of them. By absolving them of their downfield coverage against a boundary receiver, safeties can play quicker on early downs to help with the run. Offenses will create extra gaps with attached tight ends on early downs, so having a safety trigger to fill the D gap more quickly can be the difference between second-and-4 and second-and-8.
On top of the obvious help with run fits and intermediate zones — taking some of that responsibility away from linebackers with poor coverage skills — 4-read still helps to defend bubbles and hitches through a trap coverage, robbing the route with an unexpected defender. It’s a solid early down or red zone coverage call when the defense isn’t as worried about getting beat deep on a 1-on-1 matchup against a cornerback.
In the next part of the series, we’ll touch on Spagnuolo and Dave Merritt’s Cover 3 usage — which is similar to some of the match concepts that Bob Sutton used, but with more variety.
Until then, thanks for reading the Summer of Spags!