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Summer School 2020: How to identify coverages

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How do you go about identifying what coverage the defense is playing?

Every year here at Big Blue View we like to spend the weeks and months before training camp opens diving into the nuts and bolts of football.

Even in the best of years this part of the calendar is slow as the New York Giants (and every other team) only have sporadic OTAs, workouts, and mini-camps. So it’s a good time to peel back the layers and look not only at what is happening on the field, but the “why” behind what is happening.

In years past we have looked at the basic coverages used by defenses as well as some of the ways in which offenses can combine individual routes to create overarching route concepts to attack defenses. This year we we want to take things a step further to show the chess match between offenses and defenses. Why defenses choose the fronts and coverages they do, where they are strong, and how offenses can exploit their weaknesses to attack them.

How do defenses decide what coverage to play?

We’ll start on the defensive side of the field because we need a defense to identify.

Generally speaking, defenses determine their coverage schemes based on two factors. The foundation is their roster — what players they have and what their strengths are, and the coaches’ philosophic approach to defense. From there they try to anticipate what an offense will do in a given situation and put themselves in position to counter it.

Typically speaking, man coverage requires an athletic premium at the cornerback position. Corners who are added for man coverage defenses are typically tall, long, and very athletic with excellent speed and movement skills. Often they are on par with the receivers they are covering and can be even better athletes. As well, press-man coverage allows them to disrupt receivers’ timing as well as their routes within five yards of the line of scrimmage. All told, that makes gaining separation more difficult for receivers against man coverage and generally leads to lower completion rates as well as (generally speaking) a lower EPA as compared to zone coverage. However, man coverages can also lead to lower turnover rates as there are fewer defenders in any given area of the field to capitalize on a mistake and corners typically have their backs to the quarterback.

So, then, what is a defense to do if they aren’t able to secure elite athletes for their defensive secondary, or have a coach who wants to take the ball away, not just see it batted to the ground?

In those cases defenses start to look toward zone coverages. Zone coverages offer more flexibility in both play and roster construction than man coverages. Zone coverages tend have a lower athletic requirement than man coverages, as defensive backs don’t have to run with receivers step-for-step. They also allow for more flexibility as players are covering areas rather than individual players, as well as more potential for generating turnovers as zone defenders are more able to play facing the backfield. The fact that zone defenders are not in phase with receivers also makes them more difficult to block and better able to rally to the ball in run defense.

Of course, zone defense isn’t a panacea. As Giants’ fans well know, it requires communication between defenders and discipline when it comes to picking up and passing off receivers who enter or leave their coverage zones. It also demands quick — and accurate — mental processing to know when to close on receivers to defend or intercept passes.

Due to a variety of factors, between coaching preference and the general scarcity of elite man-coverage corners such as Stephon Gilmore or Patrick Peterson, defenses across the NFL roughly play 60 percent of their snaps in zone coverage and 40 percent in man coverage.

But, as we know from previous Summer School courses, there are many different kinds of man and zone defenses. To briefly sum them up (we will be getting into the specifics in much more detail in subsequent posts).

Man coverages

  • Cover 0 (pure man) - All defenders are either in man coverage or pass rushers. There are no defenders in zone coverage. Typically used for high-pressure blitz packages with the maximum number of pass rushers with a “high risk, high reward” mindset.
  • Cover 1 (man free) - One defender, the free safety, in a coverage zone in the deep part of the field. An aggressive scheme generally used for blitzing but features a deep defender to discourage offenses from taking vertical shots.
  • Cover 2 (2-man) - This is a variation of the Cover 2 defense which features two safeties in deep zones, each covering half of the field, while the cornerbacks stay in man coverage.

Zone coverages

  • Cover 2 - A classic coverage scheme which sees zone coverage underneath on the outside with the cornerbacks as well as with two deep safeties covering deep halves of the field.
  • Tampa 2 - A variation on the Cover 2 scheme which sees the middle linebacker sprint back into a deep coverage zone, turning a Cover 2 scheme into a Cover 3 scheme.
  • Cover 3 - A coverage scheme which sees the cornerbacks and free safety each play in deep zone coverages. The strong safety and linebackers each cover a zone in the short area of the field.
  • Cover 4 (quarters) - The outside cornerbacks and two safeties divide the deep part of the field into four coverage zones. The linebackers divide the shallow part of the field into coverage zones as well.
  • Cover 6 (quarter, quarter, half) - A blend of Cover 2 and Cover 4 principles. Divides the deep part of the field into three coverage zones, with a cornerback and a safety each responsible a quarter and another cornerback responsible for the remaining half.

Picking coverages

Defenses will then install the coverages they execute best based on their week of film study. When defenses study offenses, they are looking at what plays they run most often and in what situations they run those plays.

If an offense is prone to passing deeper on second-and-short yardage, the defense will pick a coverage scheme which has more coverage players deep. If the offense has a dangerous tight end they tend to employ at the fringe of the red zone, the defense will likely avoid coverages that leave seams vulnerable. We won’t be getting into the chess match any more than these generalities now — but we will be getting to them soon enough.

Identifying coverages

Okay, now we switch to the offensive side of the ball and putting ourselves in the role of quarterback. The defense has come out with a coverage they think will counter whatever play we are most likely to run. So, how do we solve that problem? Well, the first step of problem solving is to identify the problem, so let’s go through the steps to get a pretty good idea of what coverage you are facing.

Step 1 - Count the safeties

The process of identifying coverages is really a process of elimination. The first thing a quarterback wants to do is eliminate as many possibilities as possible, and the quickest way to do that is to count the deep safeties. While the number of players starting the play in the deep part of the field won’t tell you exactly what coverage is being played, it will give you an idea of what coverages (probably) aren’t being played.

  • 0 players deep - This is likely a Cover 0 defense, and an all-out blitz.
  • 1 player deep - This is probably a Cover 1 or Cover 3 defense.
  • 2 players deep - This is probably some variation of Cover 2 or a Cover 4 defense.
  • 3 players deep - This is probably a Cover 3 or a hybrid defense.
  • 4 players deep - This is probably a Cover 0 (with the players in off-man coverage) or Cover 4 defense.

Step 2 - Determine man or zone coverage

Now that we’ve counted the safeties, we have the coverage narrowed down to a couple likely options. But despite having similar pre-snap looks, a Cover 0 and a Cover 4 defense, or a Cover 1 and Cover 3 defense, will behave very differently after the snap.

If we want to know what audibles to make, what our reads will be, or which players will likely be open, we need to find out if we’re looking at a primarily man coverage or zone coverage.

(2a) Check the cornerbacks

The first thing we’ll do after counting the safeties (or deep players), is to look at how the cornerbacks are aligned.

Generally speaking, when a man coverage defense is taught, the cornerbacks are coached to take inside leverage. That is, they want to be inside of the receiver, so they can force the receiver closer to the sideline to shrink throwing windows and make it easier to force receivers out of bounds if they do make the catch.

In zone coverages we often see corners line up outside of the receivers (outside leverage). They do this to try and force the receiver towards the middle of the field where there are more defenders and more help.

(2b) Watch the response to motion

It’s very common to see a player go into motion at the start of an offensive play. Almost every play starts with a receiver, tight end, or running back moving in some way. This could be as simple as a slot receiver jogging back and forth for a few steps or a wide receiver motioning from one side of the offense to another. This isn’t simply eye-candy or something meant to confuse the defense, but is done for a very practical purpose for the offense.

By sending a player in motion, the offense is forcing the defense to declare whether the player covering him is in man or zone coverage. If a receiver motions from left right and the defender over him follows suit, that defender is (almost certainly) in man coverage. Knowing whether one defender is in man or zone coverage might not tell you exactly what you’re facing, but with the other context clues it’s usually enough to to give you a pretty good idea.

It can also be useful if the offense is targeting that particular defender to know which route concept to use to put him in a responsibility conflict. (Again, this is something we’ll be getting to in a later post, and for now is just something to keep in the back of your mind.)

Step 3 - Check the front 7

For the last part of the process we want to take a quick look at the front seven defensive players. Are they showing pressure? How are they carrying themselves?

Just like the rest of the defense, they often try to disguise their intentions, but sometimes you pick up clues based on alignment or how the defenders are distributing their weight. If a linebacker is showing blitz but has his weight back, it’s likely he’s going to retreat into a coverage zone. That can give us a hint what to expect after the snap and might be another context clue as to what kind of defense we’re facing.

Putting it in practice

Let’s go through the exercise of identifying the coverage in a real game situation.

Giants at Cowboys, Week 1 (2019)
First quarter, 6:47, First-and-10, Dallas 43-yard line

1 - Count the safeties: 1 deep safety in the center of the field

2 - Man or zone?

a) Check the corners: Corners are aligned inside of the wide receivers

b) Watch the motion: There isn’t any pre-snap motion, but we do see the defenders adjusting to the Cowboys breaking the huddle and going to the empty set. Most notably Markus Golden follows Ezekiel Elliott to the outside which suggests man coverage.

3 - Check the front 7: The down lineman and linebacker on the line of scrimmage have their weight forward, while the linebackers have balanced stances or their weight is shifted slightly back.

Conclusion: This is likely a Cover 1 defense with the cornerbacks in an off-man coverage and the linebackers covering shallow zones over the middle.

The play

This does indeed turn out to be a pretty basic Cover 1 defense from a nickel set. Dak Prescott opts for the quick 5-yard pass to Randall Cobb, to which Janoris Jenkins quickly reacts and knocks down for the incompletion. Prescott did identify Cobb as open, but Jenkins was able to close the passing window by the time the ball arrived.

(Note: What we don’t know is if Prescott didn’t see Markus Golden (44) motioning out to play outside cornerback, or if Elliott wasn’t in the progression at all and was simply a decoy. While he should obviously expect Antoine Bethea to rotate his coverage that way, there is a sizable passing window as Golden is beaten and it take Bethea too long to get to the sideline.)