Xs and Os: Cover-4

In recent years, a number of site visitors have written in and requested a feature whereby some of the X's and O's behind the Browns were explained. Thanks to Lane and some other knowledgeable folks, even a beer-swilling neophyte like me can pretend to understand this stuff. With the Pittsburgh game coming up, we're going to deal with a coverage scheme suggested for attacking the Steelers known as a "Cover-4".


In recent years, a number of site visitors have written in and requested a feature whereby some of the X's and O's behind the Browns were explained. We've considered doing this for a while, waiting patiently for some knowledgeable coach or other Wizard-like figure to step forward and offer to write brilliant, incisive columns for knowledge-hungry Browns fans. That hasn't happened, so you're stuck with me.


I know nothing about Xs and Os other than it would make a nice concept for a breakfast cereal. I love football, but my expertise has always been more in when to cheer and finding the beer vendor. That makes me a blank slate about strategy (already obvious to anyone who has been reading the site for a while), so writing these columns gives me a chance to learn something and take anyone interested along for the ride.


Today, we're going to deal with a coverage scheme known as a Cover-4. I've turned to Lane, some other experts who talked to us, and a couple of books to help me. Assume anything intelligent comes from those sources, and anything wrong comes from my inability to comprehend it. Feel free to write me if you have comments.


What the heck is a Cover-4?


The reason I'm interested in this is a story by ESPN's Eric Allen which tried to analyze the Browns – Steelers match-up in a couple of paragraphs. Allen dropped the Cover-4 bomb in describing how the Browns should deal with Hines Ward and Plaxico Burress. Allen suggests the Browns should be real concerned about those two burning them deep and recommends a Cover-4 to make all our lives better.


The Cover-4 is a zone defense that is intended to slow down pass-happy teams, particularly those who have a tendency to throw downfield. With Burress and Ward, the Steelers have two weapons that can stretch the field, and the Browns have to figure out how to avoid getting severely burned deep. The team has had a problem in the past with giving up the big pass play or run, although that hasn't been as big an issue in 2002.

Figure 1: Cover-4 Coverage Scheme


The idea behind a Cover-4 is that the safeties and cornerbacks are all going to patrol the deepest areas of the field. Since that is four players, they essentially split the field into fourths and each head into a zone (one of the shaded circular areas in figure 1).


Cover-2,3,or 4 Strengths and Weaknesses


I think we have all heard the term Cover-2 thrown around a lot this year. For unexplained reasons, it's the TV analyst technical-phrase-of-the-year. There's a lot in common, as you would guess, between the Cover-2 and Cover-4. The differences between the two, however, are critical.


In a Cover-2, the deep zones are split into two, with each safety taking half the field. Likewise, a Cover-3 is a coverage where the deep field is chopped up into thirds. So, when you hear the terms, Cover-2,3, or 4, the number is referring to how many defensive backs have been assigned to patrol the deep zone. If you're really worried about long pass plays, you will tend to put more players back there, which is why Allen suggests the Cover-4.



Each one of these zone coverage approaches has their own challenges. A Cover-2, where the entire deep zone is patrolled by two safeties, puts a lot of pressure on the safeties to patrol the deep zone. The Cover-2 defense's weakness is down the middle or seam where the safeties are split. A Cover-4, on the other hand, sends both the safeties and corners deep, which creates more space underneath in the middle zone, as well as reducing the amount of available run support.


The good news, as Allen indicates in his little strategy blurb, is that it creates a two-on-one coverage situation if you have two wide outs (namely, Burress and Ward) running deep.


How to Beat the Cover-4


There are really two challenges to a defense running a Cover-4. One has to do with a strategy that offenses can use to attack it, and the other has to do with the skills of the defense running it.


The first challenge is strategic. It is possible for an offense to flood the middle zone if it is faced with a Cover-4, since it emphasizes deep coverage. This can create mismatches with the linebackers and defensive ends that would have to monitor that space. The key here is for the linebackers to get some help from safeties. Depending on the offensive alignment, the defense will need to adjust its approach, particularly with what the strong safety does.


In speaking with some experts while writing this article, we were told that the best way to consistently beat the Cover-4 is to run or flood a zone, thus causing the defense to react to the offense. When that happens, the defense becomes susceptible to a pass down the seam.


The second challenge has to do with personnel. One area of concern in the Cover-4 defensive scheme is the ability of the linebackers in pass coverage. Oftentimes, a quarterback will attempt to drop the ball into the soft-spot of the defense that usually resides between the linebackers and defensive backs. The free safety or coverage safety will generally assume more of the natural pass defense flow, in an attempt to assure defensive integrity in the intermediate to long passing game.


When a zone is flooded in the short to intermediate zone, either a defensive lineman, linebacker, or safety will flow into the zone. But that requires strong pass-coverage skills by whoever is responsible. In most cases, this is what caused teams in the NFL to commit to nickel defensive packages instead, thus getting more athletic, coverage-type players on the field.  


How to Run It Well


Despite the challenges, variations of the scheme have been employed by keen defensive coordinators. The defense employed by Bill Belichick in New England is a perfect example. The Patriots will show either Cover-2, 3, or 4, deploying as many as seven defensive backs into the scheme.


The abilities of the defensive line are key to running a Cover-2, Cover-3, or Cover-4 effectively. The defensive linemen to need to be able to create a pass rush, while maintaining gap integrity. If the line can't meet the challenge, the opportunity is presented for an offense to take advantage of physical mismatches in size and strength with so many coverage-type players on the field.


If the defensive line cannot provide that rush, the defense is forced to utilize a linebacker or defensive back at or near the line of scrimmage. This naturally causes problems with the attempt to deal with the flooding of the intermediate zone.


The advantage of a Cover-4 is that when played properly, the scheme will minimize the probability of a big play. Additionally this defense can create turnovers due to a quarterback becoming impatient or making an incorrect throw or read.

The Importance of Hiding the Scheme


It is difficult for offenses to tell whether a team is in Cover-2 or Cover-4. The difference is critical, because weaknesses in the cover schemes are different… the offense has to attack them in different ways. So hiding whether you have a Cover-2 or Cover-4 on is important. We've been told that, once again, New England is a real good example of a team that excels in hiding this coverage scheme.


There is a tip-off that can help offenses, however. Because of the different nature of the coverages, there might be a difference in where the safeties are lined up. Typically in a Cover 2, where the safety has to own half the deep zone, they will line up outside the hash mark. In a Cover 4, it will be on the hash mark. Spotting this alignment will allow a quarterback to understand whether the deep or middle areas will be more likely places to attack.



Conclusions Reached by Beer-Swilling Neophyte


After learning more about the Cover-4, I guess that I'm not sold on Allen's recommendation. Like most "national" analysts, in my opinion, Allen focuses too much on star players and designs the scheme around stopping them.


There would be two problems with the Browns using this scheme, in my opinion. The first is that I'm very worried about our defensive line's ability to meet the requirements of mounting an effective pass rush working alone. Based on what we've seen so far this year, the Browns don't have the speed pass-rushing DE to put enough pressure on Maddox.


The second problem I have with it is the effectiveness of the Steelers offensive line and their three-pronged running attack. Noting that the best way to beat the Cover-4 is though running and flooding a zone, I suspect that the Browns would be setting up the Steelers for a big day of ball-control. As a fan who watched Jerome Bettis dominate the clock, and the Steelers dominate the line of scrimmage, in their second matchup in 2001, this makes me very nervous.


Then again, I'm a neophyte and a little knowledge is a dangerous thing. It will be interesting to watch the game tomorrow and see if Fazio decides to take Allen up on his idea.


- AB

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