CORNERBACK

A 'cornerback' ('CB') (also referred to as a 'corner') is a position in American and Canadian football. As a critical element of any defensive secondary, the cornerback position demands players have speed, agility, height, and exceptional instincts for reacting to mid-long range football throws. Additionally, a cornerback's skillset typically requires proficiency in backpedaling, jumping through traffic, man-on-man (single) coverage, disrupting pass routes, jamming receivers at the line of scrimmage, reading the quarterback, understanding zone coverage, and open-field tackling.
Most modern NFL defensive formations use four defensive backs (two safeties and two corners); CFL defenses generally use five defensive backs (one safety, two defensive halfbacks, and two corners).
A corner's responsibilities vary depending on the type of coverage called. For instance, in man on man coverage, a cornerback's responsibilities lie primarily in covering his assigned receiver on the opponent's team; the cornerback will attempt to shadow the receiver once the play begins, and will continue to follow the receiver stride for stride as the offense attempts to execute its play. Again, coverage is simply how the defense assigns protection to its defensive secondary to handle the offense. In terms of defending passing plays, a corner will be typically be assigned either zone or man-to-man coverage.
=Zone coverage=
An essential form of corner coverage involves "zone" coverage, in which case the cornerback becomes responsible for securing an assigned portion of the playing field. In zone coverage, the cornerback is responsible for a specific area of the field; the cornerback will focus only on opponents who challenge his designated area of coverage and will generally ignore players outside of his prescribed zone. Zone coverage may consist of any number of schemes and variations and gives defensive coordinators great flexibility in confusing and challenging offensive plans.
When developing a defensive strategy utilizing zone, areas of the field are assigned accordingly to players ranging from the flats, mid range zones, and deep zones. More advanced forms of coverage can involve "quarterback spies" and "containment" coverage. In a basic zone package, flats refer to the immediate left and right of the line of scrimmage, and zone coverage in the flats typically demand a corner or linebacker to cover roughly five yards into the defensive field. Mid-zone coverage demands intermediate coverage either to the right, middle, or left of the defensive backfield from roughly five to twenty yards from the line of scrimmage. Areas such as the "deep third" split up the deeper, long range part of the field, and quarterback spies assign players to focus only on the quarterback in semi-zone coverage.
The terminology for basic zone packages is intuitive; Cover 2 typically has both safeties splitting the deep part of the field into two halves, essentially dividing the deep field responsibilities between each other evenly. The "Cover" part of the terminology refers to a zone-type coverage involving defensive backs, while the number designates how many deep zone responsibilities there are.
One fundamental type of zone coverage is called "cover 2" or a "2 deep zone", where two safeties split the deep range area of the field into two zone halves, leaving the rest of the defensive secondary in either man to man or short to mid range zone coverage. The Cover 2 is popular among defensive coordinators, particularly in the National Football League, because the scheme is relatively simple: it allows maximum use of the defensive secondary without getting too deeply entrenched in committing to either the run or the pass and allows defensive backs to keep the progression of the play in front of them. Additionally, the typical Cover 2 schemes has the cornerbacks mirrior each other's responsibilities; if one corner is in man to man, it is likely that the other is in man to man as well.
In a "Cover 3" each defensive back is responsible for covering his designated "deep third" of the field: the outside thirds (hence the term corner) of the field are assigned to the left and right cornerbacks while a safety (usually the free safety) covers the middle third, leaving the strong safety to either play man to man or move into the "box" to roam around the line. Similarly, a Cover 4 would put two corners and both safeties into deep zone coverage splitting the field into four areas of zone coverage.
Zone coverage is not always simple, however. Experienced defensive coordinators such as Wade Phillips and Jim Johnson utilize varied zone packages and complex assignment responsibilities to disrupt passing attacks and confuse opponents. For instance, one variation of the Cover 2 allocates the weak-side cornerback (the "left cornerback") to cover half the field in order to free up a safety, the idea being to allow the safety to engage a different part of the field, blitz, contain, or spy. The strong side cornerback (the "right cornerback") may be in a variety of different alignments which may include "loose man", "man-under", or "man-up". Although these are one-on-one coverages, more often than not his responsibility is usually limited to an initial funneling and subsequent drop back into a zone called the "void". This is a pie shaped slice of field included with your most basic 2 deep zone coverage. One interesting aspect sometimes encountered in cover 2 is that it is possible for one corner to be in a zone coverage where he funnels and drops into the void, while the other corner is in man coverage. However, your basic garden variety 2 deep zone usually employs the two safeties to share half the field responsibilities, with the two corners funneling.

Contents

Single or man coverage

Jamming a receiver

Playing up

Playing off

Man on Man strategy

See also

Single or man coverage

In man coverage, the cornerback is solely responsible for the receiver assigned to him. Typically, the cornerback lines up across from his assignment on the line of scrimmage. Once the play begins, the corner may either attempt to "jam" the receiver at the line, play directly off the receiver, or concede a few yards and play with "cushion".

Jamming a receiver

When jamming a receiver at the line, the cornerback attempts to hold up the receiver at the line of scrimmage; by impeding the receiver's progression in running his assigned offensive route, the cornerback can provide his blitzing teammates more time to reach the quarterback and either end the play via a sack or force an ill timed throw. This particular method of man on man coverage is very risky and is not used lightly by defensive coordinators. Some wide receivers are either too quick or too powerful when matched up against most cornerbacks and can usually slip out of an attempted jam at the line. This can be particularly troublesome for a defense; depending on the degree of failure when attempting to jam the receiver, the cornerback may find himself beaten almost immediately if the wide receiver can exploit his proximity to the line of scrimmage. When a jam fails, the cornerback is usually flat footed and has his hips turned opposite the direction of his assignment. Wide receivers who can break through and move past a jam are able to rapidly create passing lanes and space, thus resulting in big play opportunities for the offense. Nonetheless, jamming the wide receiver can be very disruptive and is particularly helpful in the red zone: the closer to the goal, the more likely jams will be attempted to prevent receivers from ever engaging their routes.

Playing up

When playing up, the corner allows his assignment a free release, opting instead to mirror and follow the wide receiver stride for stride. As the wide receiver attempts to progress through his prescribed route, the cornerback will follow closely, hoping to stay close enough to make a play on the ball should a pass come his way. Playing off is usually the standard for technique in terms of coverage, as there is no extenuating risk involved.

Playing off

As a strategically preventative measure, cornerbacks are sometimes asked to play off their man assignments with a "cushion" of space; the cornerback lines up across from his assignment as usual, but begins the play with several yards between him and the receiver. The additional yardage is preventative in nature and allows the cornerback to ensure the wide receiver does not escape coverage for a big play. Playing with cushion is usually reserved for either "3rd and long" situations, late game tactics defending a lead, or for elite wide receivers.

Man on Man strategy

In terms of technique, the cornerback is typically not tasked with keeping his assigned wide receiver "inside" of him. For example, for man-coverage in the "red zone" (an area between the goal-line and the twenty-yard line) it's better to prevent the receiver from going inside (towards the middle of the field such as in a crossing route or a quick-post) because these routes are difficult to stop, especially when there's a lot of traffic on the inside. Although illegal, defenders are easily "picked" by opposing receivers and sometimes by their own teammates. To avoid this, it is favorable for cornerbacks to line up close to the line of scrimmage if the ball is inside the 5 yard line, and force the receiver toward the sideline (outside) without violating the 5 yard no touch rule.

See also

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★ American football defensive schemes

★ Cornerback defense