How do you bring a lot of pressure on the quarterback, while still making sure everyone is covered?
One way defenses can do this is by running what's called "Cover 0" (Or Cover Zero- depending on how you want to spell it).
Many coverages can be identified by the number of high safeties that are helping underneath coverage. So for example, in Cover 1, there is 1 safety over the top. In Cover 2 there are 2 safeties. Cover 0, there are 0. In the case of cover 2, or 3 - those are zone coverages.
Cover 0 falls in the man to man category. Cover 0 is an interesting coverage in the sense that everything is very simple, everyone has a clear job with not a lot of room for misunderstanding.
How does Cover 0 work?
In the coverage known as Cover 0, there are 0 safeties over the top of the coverage helping the underneath defenders. Those defenders are in man to man with no extra help to rely on.
Cover 0 is a man to man defense. Every player that is not a defensive lineman (and sometimes lineman) has a job. They are either recovering an offensive player man to man, or they are applying pressure by stunting or blitzing.
Why do defenses use Cover 0?
The purpose of a Cover 0 coverage is to bring the maximum amount of blitz pressure while still making sure that all of the eligible offensive receivers are covered. You do this when you are adding more players, usually 6, to the line of scrimmage. Depending on your defense, you’re either rushing 3 or 4 on a normal play, but if you want to rush up to 6 players, Cover 0 is a simple way to make sure every player is covered while you’re bringing more players to the line of scrimmage to rush the quarterback.
What are the Strengths of Cover 0?
Cover 0 is an easy way to make sure that all of the offensive skill players are covered. Your skill players on defense, are covering their skill players on offense. In the event the offense motions, it is easy for your defense to adjust, because it is man to man coverage. If your man moves, you move with him. With all of their skill players covered, it allows you to add more players to the line of scrimmage, whether you’re trying to stop the run, or rush the passer.
The defense works great against the run, because more of your players are being added to the box traditionally. In zone coverage, players have to read pass or run, but in Cover 0 the assignments become much more concrete. The assignments are black and white. There are players in coverage, and there are players being added to the line of scrimmage.
Stopping the Run-Pass Option
Cover 0 is ideal against a heavy RPO team as well. The Run-Pass Option gives the offense a decision on whether to run it or throw it after the snap of the ball. When all of the receivers are covered, Cover 0 will limit throws, and with a defense presumably bringing 6 to the line of scrimmage, it will also help the run.
In contrast to zone coverage, where most defenders have to keep one eye on the quarterback to take away the run, cover 0 means that the players in coverage should keep their eyes on the wide receiver, tight end, or running back they're covering, so it should be a lot harder to influence them with the RPO.
Breaking on Short Routes
In terms of the pass, Cover 0 does well against both short and quick breaking routes, such as a hitch or a slant because your defensive back is solely in coverage with no run responsibilities, so there is no reading run or pass. Cover 0 can also be helpful against a heavy screen team. Conversely, cover 0 works great against long routes as well due to the amount of pressure you’re able to send. An offensive line is built of 5 players, and cover 0 allows you to bring 6, reducing the time the quarterback has to throw immensely.
Depending on how well a defense disguises their intentions, cover 0 can very easily look like cover 4 pre snap, especially against a balanced 2x2 formation, so the quarterback may not always be ready to get rid of the ball in a hurry and can be caught off guard.
What are the weaknesses of Cover 0?
The weaknesses of Cover 0 are what makes it so strong in some respects. You're bringing a lot of pressure, so it is a high-risk/high-reward play call. You can either sack the quarterback, or force a bad throw or a fumble, but if one of your cover guys gets beat he has no help, since any deep defenders playing a few yards off are responsible for specific eligible receivers, and it can easily go for a big play for the offense.
Defensive backs and linebackers are covering man to man and it is easy to have your wide receivers “run them off” so to speak by running deep routes thus pulling 5 players away from the line.
Vulnerable to the Run?
It can also be susceptible to the draw play, where the offensive linemen block like a pass play and as the pressure gets up the field, the quarterback simply hands the ball off to the running back. In this case, if the defenders rush too far up the field, and your defensive backs are in single coverage, there may be nobody to tackle that back. You’re hoping in this situation, that the blitz gets to the back, before he gets past them.
Additionally any type of quarterback scramble can be harmful vs. a Cover 0 defense because again, all of those players you have in coverage are focusing on their man, and not on a QB leaving the pocket and running.
Pick Plays in the Pass Game
A “pick play” can also cause issues for a Cover 0 defense. This happens for example, when two wide receivers cross their routes over each other. Similar to the wide receivers switching routes one receiver will run a route and “pick” aka run into a defender, allowing his teammate to go free. At the very least In this case the offense is hoping that the defenders are going to collide or naturally cut each other off. The mesh concept is a good example of a pick play that can create separation against man coverage. In another version of man to man, Cover 1, there may be a safety there to help cover that player coming free, but in cover 0 there is no help over the top, and in many versions there isn't any help in the middle of the field either.
"MOFO" - Middle of the Field Open
Cover 0 is what many coaches refer to as a "middle of the field open" coverage, because, well, the middle of the field is open. There is no defender sitting deep in the secondary to take away the post. Legendary Raiders owner Al Davis was well-known for his rule about cover 0- Raiders defensive coordinators were forbidden from running it, since he hated to give up the deep middle and leave it uncovered. He always wanted at least a free safety sitting deep as the last line of defense in case an offensive player ever broke through.
Cover 0 Rules
Different teams have different specific rules and their own technique for how to play cover 0, and this article could never be long enough to cover all of them. Still, what you'll see below is a pretty general version of how most defenses will play the cover 0 scheme, from high school all the way to the NFL.
The secondary and defensive backs will be locked up in coverage, while the linebackers bring pressure from the box and force the quarterback to make a split second decision one way or the other.
Left Cornerback - Man to Man Coverage on Z receiver - Be ready to break on any thing short - Expect no safety help
Right Cornerback - Man to Man Coverage on X receiver - Be ready to break on anything short - Expect no safety help
Strong Safety - Man to Man Coverage on the tight end - Be ready to break on anything short
Free Safety - Man to Man Coverage on the slot receiver - Be ready to break on anything short
Sam Linebacker - Man to Man Coverage on the running back - Bring pressure if the back stays in protection
Mike Linebacker - Blitz through right B-gap - Show the blitz late pre snap
Will Linebacker - Blitz through left A-gap - Show the blitz late pre snap
Cover 0 Variations
Just like before, these are some very general defensive terms, but even if teams don't play these exact techniques, most coaches will recognize the terms, and the different ways to bring pressure from the strong or weak side.
Cover 0 “Rat”
Normally in cover 0 you’d rush 6 defenders. In Cover 0 “Rat” you’d rush 5, and leave one player to cut off crossing routes and keep an eye on the quarterback lest he breaks the pocket and tries to run.
In this example, the Will linebacker is sitting in the middle, playing a "Rat" technique, and in position to either take away any routes breaking inside, or any plays where the quarterback takes off and tries to run. While the rest of the secondary is locked up in man coverage, the Will is a free player in perfect position to take away the easy throw that the quarterback is trying to make.
These are the types of schemes which are great at anticipating the kinds of answers an offense has, and taking them away.
Dropping Defensive Linemen into Coverage
This one is as simple as it sounds. If you have a player on your defensive line that is more of a hybrid, meaning that he can rush and cover, lining him up as a defensive lineman and having him cover a back for example could add another wrinkle to your Cover 0.
In this example the defense has decided to put him in man coverage versus the running back, taking away any kind of screen or flare route. If the running back stays in pass protection, the end can still come after the quarterback, blitzing through the open gap.
This scheme can also be merged with the "Rat" coverage we talked about in the example above, where instead of the Will linebacker dropping into the middle of the field, it's the defensive end as the free player.
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