Cornerback

For corner back, the Gaelic football and hurling position, see Gaelic football and Hurling positions.

A cornerback (CB) (also referred to as a corner) is a positional role played by a member of the defensive team in American and Canadian football. A cornerback is a member of the defensive backfield or secondary, which also may include the safety and linebacker positions.

The rules of American professional football (NFL Rulebook) and American college football (NCAA) do not specify starting position, movement, or coverage zones for members of the defensive team, except that they must be in the defensive zone at the start of play. The positions, movements and responsibilities of all defensive players are assigned by the team. The positional roles are therefore customary, not assigned by rule but by patterns of coverage assigned by the coach or defensive captain before the play begins. These roles have varied over the history of American football.

The principal defensive responsibility of the cornerback is to legally interfere with or intercept a forward pass attempt made by the offense. Other assignments may be to tackle a ball carrier from the opposing team carrying the ball, or to blitz, or enter the offensive backfield after the start of play in an attempt to tackle a ball carrier on the offensive team.

The rules to how one may go about this are different at different levels of play. For example, in the professional level, a cornerback is not allowed to make any contact with an eligible receiver after five yards; whereas any level under professionals can maintain some contact in order to know where the receiver is. If a cornerback is judged to violate these rules of contact with a receiver, the penalty they receive is most commonly pass interference depending on the extent to which the rule is violated.

The role of a cornerback (or safety) in coverage is to act as a "shadow receiver" for forward passes. He is assigned either to a specific offensive receiver (in man-to-man coverage) or within a certain zone of the defensive playing field (zone coverage.) The rules of legal coverage allow both offensive receivers and defensive coverage to have a fair and unimpeded chance at catching a thrown ball. A defensive player in coverage may disrupt the ball in flight or during an attempted catch, but may not push or strike the opposing player in order to impede his ability to catch the ball. Violation of the rules by either the offensive or defensive player is referred to as pass interference and the offending team is assessed a penalty.

As a critical element of any defensive secondary, the cornerback position demands players have speed, agility, and exceptional instincts. Additionally, a cornerback's skillset typically requires proficiency in backpedaling, shedding blockers, man-to-man 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 how the defense assigns protection to its defensive secondary to handle the offense. In terms of defending passing plays, a corner will be typically assigned to either zone or man-to-man coverage.

A high school cornerback (#8) in single coverage using the "loose man" technique.

Zone Coverage

In zone coverage, the cornerback defends an assigned area of the field. Many schemes and variations were created to provide defensive coordinators great latitude and flexibility which aim to quell offensive schemes.

When utilizing zone coverage, some areas of the field require special attention when defending against specific pass plays. They include the flats (to defend the screen pass and hitch routes), mid range zones including the void (to defend the "stop n go", quick post, fade, hook, curl, and "sideline" or "out" routes), and finally the deep zones (to defend the post/deep post, chair, streak, "fly", "go" , bomb, or hail mary routes). These are basic terms (perhaps the most generic) for the basic zones and routes which vary system to system, league to league, and team to team.
Advanced forms of coverage may involve "quarterback spies" and "containment" coverages, as well as various "on field adjustments" that require shifts and rotations, the latter usually initiated by the captain of the secondary (typically the free safety) during the quarterback's cadence. At this time the captain attempts to "read" the alignment(pro set, split set, trips,(etc.)of the offensive "skill players" (backs and receivers) in order to best predict and counter the play the offense will run. He will base his decision on past experience, game preparation, and a sound comprehension of his teammates strengths, abilities, and tendencies. These adjustments may change on a play by play basis, due to substitutions or even evolving weather or field conditions. For example, defensive coordinators may favor a tendency to play a less aggressive containment style zone coverage during wet or slippery field conditions to avoid problems associated with over-pursuit (when a defender takes a poor angle on a ball carrier and cannot redirect in time due to poor footing or loose sod).

Cover 2

The Cover 2 (Two), also called the Tampa 2 because of the Buccaneers frequently using it, 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. Also, it allows defensive backs to watch the play develop in front of them as opposed to having their backs turned to the ball at any time. Cover 2 is a "2 Deep Zone" that uses 4 defensive backs. Two safeties line up 11-15 yards off the line of scrimmage (usually each safety stands on or a few feet from his hash mark), while cornerbacks line up around 5 yards from the wide receivers closest to each sideline.

In Cover 2, the cornerback is usually responsible for "containment". This is where he does not allow anyone to run outside of him (between him and the sideline). He then funnels or jams receivers towards the middle and within 5 yards, reads the quarterback, and finally drops back to defend the void if there isn't a throw to the flat or a running play. Typically with the Cover 2, cornerbacks mirror each other's zone responsibilities. However, sometimes they play a "man-up" style bump and run, a form of bump and run designed to eliminate the short pass, where the receiver is forced to the near sideline, which is the opposite of the run oriented "containment" style of Cover 2. Usually if one corner is in man to man coverage, the other is in man to man coverage as well. The two safeties act as a security blanket for deep routes.

Cover 3

In a "Cover 3", the two corners and free safety defend their assigned deep thirds of the field, where the corners defend the outside third, (hence the term corner) while the safety defends the middle third. This allows the strong safety to address a full range of duties depending on what reads he makes coupled with the coverage called. These duties may simply include single or zone coverage, being a quarterback spy, providing extra run support in short yardage situations, or to stunt or blitz through a gap or from the end.

Cover 4

In a "Cover 4" each defensive back is responsible for covering his designated "deep fourth" of the field, while other defensive players are responsible for covering the underneath areas. Sometimes Cover 4 is used as a "prevent defense".

Variations of these coverages exist to counter the many styles of offenses a defense may face on any given week. For example, one variation of the Cover 2 allocates the weak-side corner (eg: typically the "right cornerback" when playing against right-handed quarterbacks) 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 "left cornerback") may be in a variety of different alignments which may include "loose man", "man-under", or "man-up". Although these are forms of single coverage, more often than not his responsibility is usually limited to an initial jam and funnel with a subsequent drop back into the "void". This pie-shaped slice of field is included with your most basic 2 Deep Zone coverage. One interesting aspect sometimes encountered with Cover 2 is that it's possible for one corner to be in a zone coverage, where he funnels and drops into the void, while another may be 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.

Jamming the receiver

When a cornerback is attempting to jam or funnel a receiver, he is trying to disrupt the receiver's route at the line of scrimmage. By impeding the receiver's progress, the corner can provide his teammates with extra time to sack the quarterback (sometimes called a "coverage sack"), or force an ill-timed throw. In addition, a proper jamming allows the safety or linebacker to provide stronger run support because he then has more time to drop back into zone coverage in the event of a pass. In other words, he has been granted more time by the corner to recover from his mistakes if he anticipates a run when in fact the play is a pass.

If the jam fails, the cornerback is usually flat footed and not in a suitable position to defend the mid to long-range passes. When this occurs, the safeties and linebackers usually cannot return to their zone obligations in time, especially if they were anticipating a run as the play began. In essence, the defense is unnecessarily "stretched" to its breaking point. Receivers who can effectively avoid the jam and stretch defenses are far more likely to create big play opportunities for the offense. Therefore, it is vital that a cornerback execute a proper funnel or jam to allow safeties and linebackers enough time to return to their zone responsibilities in the event of an unforeseen pass play. By working together and familiarizing where ones help may come from, a higher degree of confidence is established amongst the defensive secondary as a unit, with the end result translating into a much more formidable defense against both the run and pass.

Single/man-to-man coverage

In single or man to man coverage, the cornerback is responsible for a particular receiver assigned to him. As the play begins, the corner may either attempt to "jam" the receiver at the line, play a step or two off of him, or concede a few yards and play with a "cushion". Cushions can range from a yard or two, to forty yards in a "prevent defense" situation. Cushion is just a term used to describe how far off the defender plays away from the offensive player he is assigned to defend. Generally, cushions are smaller in single coverage and larger in zone coverage.

Single coverage in the "red zone" (an area between the goal-line and the twenty-yard line) is usually designed to prevent receivers from slanting towards the middle of the field. These types of routes are difficult to stop in the red zone because this area is usually congested with bodies colliding, crossing, and weaving in different directions. Although illegal, defenders are easily picked or screened (this is illegal yet hard to enforce in short field, congested situations) by opposing receivers and sometimes by their own teammates. To avoid this, it is often favorable for cornerbacks to either: "switch" assignments (where he will agree beforehand to trade assignments with one of his fellow defenders in the event that the receivers criss-cross as the play begins), or alternatively, a corner may instead line up close enough to the receiver (very close) at the line of scrimmage to force or jam him toward the sideline (outside) without violating the 5 yard no touch rule. Corners often refer to this second style of coverage as the "man under" technique.

Single coverage, or man to man coverage usually employs relatively few techniques. However, they are often initially displayed to resemble one another as much as possible to disguise the true motives of the defense, and be interchangeable as well. Terminology for single coverage may vary, yet they all share a common general purpose which is to prevent the receiver from catching the ball. For an attempt at cohesiveness, a few generic terms have been included with the effort to estabilish a general understanding of cornerback philosophy and how his function relates to the rest of the defense. Subtle differences of course exist in regard to terminology and defensive philosophy as no two teams are exactly alike.

Man under

This man to man technique is very similar to the man up technique described below except there isn't a free release. The corner usually attempts to force the receiver toward the near sideline and jam him in order to prevent him from running toward the inside or middle of the field. To do this, the corner lines up as close as possible to the receiver without being penalized for being offsides. This coverage is used in goal line situations, as well as when a blitz is called. During this coverage, the corner doesn't have anyone to help him cover the receiver if he runs inside because his usual help is blitzing or in single coverage as well.

Loose man

Loose man requires cornerbacks to play off the receiver with a five to ten yard cushion. He usually doesn't touch the receiver and tries to keep his head on a swivel while remaining indifferent upon which direction the receiver decides to shape his route. Typically with loose man coverage, the cornerback has little or no help from the safety in defending against the receiver.

Man up

By far the most challenging, the man up technique grants the wide receiver a relatively free release as the corner shadows him stride for stride everywhere he goes. The cornerback's objective here is to position himself between the quarterback and the receiver, without knowing where the receiver is going. As the ball is snapped the corner will initially ignore the quarterback, turn and run with the receiver and hope the ball doesn't drop out of the sky before he can react to it. Corners must also hope the receiver doesn't change directions when its time to sneak a peak at the quarterback in effort to discover where the ball is. A wet field makes this coverage extremely difficult. In addition, a perfect throw is close to if not impossible to stop. This coverage is reserved for the elite cornerback as it is in this coverage where corners are most frequently beaten.

See also

• Category:American football cornerbacks
• American football defensive schemes
• Cornerback defense