Description

A cornerback (CB) (also referred to as a corner) is a member of the defensive backfield or secondary in American and Canadian football.^[1] Other members of the defensive backfield include the safeties and occasionally linebackers. Similarly to offensive skill players, the cornerback position demands exceptional speed and agility. A cornerback's skillset typically requires proficiency in reading the quarterback, backpedaling, executing single and zone coverage, disrupting pass routes, shedding blockers, and tackling.

Overview

The chief responsibility of the cornerback is to implement his coverage skills and tackling abilities to defend against the forward pass. Also, the cornerback must stop the ball carrier from advancing the football into field goal range and especially the endzone. The rules of American professional football (NFL Rulebook) and American college football (NCAA) do not mandate starting position, movement, or coverage zones for the cornerback or any other member of the defense for that matter. There is no "illegal defense" formations such as in basketball. Cornerbacks can be anywhere on the defensive end of the field at the start of play although their proximity, formations, and strategies are outlined by the coaching staff or captain.

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.

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). 

CFL

Warriors