American football teams’ defenses employ two types of pass coverage: man-to-man and zone coverage. Both coverages have many variations and combinations, but the core of every defense’s coverage begins with either the man-to-man concept or a zone concept.
Man-to-man coverage in football
Simply stated, man-to-man coverage is when any defensive back, or maybe even a linebacker, is assigned to cover a specific offensive player, such as a running back, tight end, or wide receiver. The defender must cover (stay with) this player all over the field until the play ends. His responsibility is to make sure the receiver doesn’t catch a pass. The most important rule of man-to-man coverage (which is also known as man coverage) is that the defensive back must keep his eyes on the player that he’s guarding or is responsible for watching.
Here are the three main types of man-to-man coverage:
Man free: All defensive backs play man-to-man coverage except the free safety, who lines up or drops into an area and becomes a “safety valve” to prevent a long touchdown completion. This style of coverage is used when the defense blitzes, or rushes four or five players at the quarterback.
Straight man: The free safety doesn’t serve as a safety valve in this alignment — or, as coaches say, no safety help is available. Each defender must know that he (alone) is responsible for the receiver he’s covering. This style of man-to-man coverage is generally used when the defense is blitzing or rushing a linebacker toward the backfield, hoping to sack the quarterback.
Combo man: This category contains any number of combinations of man-to-man coverage. For example, when a team wants to double-team a great wide receiver (with two defensive backs), it runs a combo man defense. The object of such a defense is to force the quarterback to throw the football to a less-talented receiver.
In the following figure, the cornerback (CB) is responsible for the star receiver’s outside move, while the safety (S) is prepared in case the star receiver decides to run his route inside, or toward the middle of the field.
A team’s pass defense may be vulnerable on the side of the field opposite where it’s double-teaming a receiver. Also, the pass defense may be vulnerable to a short pass on the same side of the field and underneath the double-team.
Zone coverage in football
In zone coverage, the defensive backs and linebackers drop into areas on the field and protect those zones against any receivers who enter them. The biggest difference between zone coverage and man-to-man coverage is that in the latter coverage, a defender is concerned only about the player he’s covering. In virtually all zone coverages, two defensive backs play deep (12 to 15 yards off the line of scrimmage) and align near the hash marks.
Here are the main features of zone coverage:
Each defensive back is aware of the receivers in his area, but his major concentration is on the quarterback and reacting to the quarterback’s arm motion and the ball in flight.
For defensive backs, zone coverage is about sensing what the offense is attempting to accomplish against the defense.
Each defensive player reacts when the ball is in the air, whereas in man-to-man coverage, he simply plays the receiver.
The simplest way to recognize a zone defense is to observe how many defenders line up deep in the secondary. If two or more defensive players are aligned deep (12 to 15 yards off the line of scrimmage), the defense is in a zone.
Eight men in the box
Eight men in the box refers to a setup that enables a team to defend the run more effectively when it has a strong secondary. The box is the imaginary area near the line of scrimmage where the defensive linemen and linebackers line up prior to the offense putting the ball into play. Usually, a team puts seven defenders, known as the front seven, in that box. But a team can put an eighth man — the strong safety (SS) — in the box if it has two outstanding cornerbacks (CB) who can cover wide receivers (WR) man to man.
The Nickel 40 defense
The Nickel 40 defense is strictly a pass defense that can employ either a linebacker or another defensive back as the sixth player in pass coverage. The sixth, or dime back (DB), position can end up being a defensive back, as well as a linebacker at times. In this alignment, the linebacker aligns in the middle about 5 yards away from the line of scrimmage.
The object of the Nickel 40 is to pressure the quarterback, hoping to either sack or harass him. Teams use their four best pass-rushers on the field in this alignment, and these four players will most likely be opposed by only five offensive linemen. Defenses use a Nickel 40 defense only when the offense uses three or more receivers in its alignment.
The Nickel 40 is a good defense against an offense that’s fond of play-action passes (when the quarterback fakes a handoff to a running back, keeps the ball, and then attempts a pass) or against an offense that likes to substitute a lot of receivers into the game.