Hi TSTers, it’s going to be very boring from now until training camp starts. Seeing how I don’t know, or pretend to know, everything about football …..I wanted to use this time to learn more. I didn’t write this but I went out and found the parts to put this together in one nice location. I’m sure there are other people on this site who want to learn more about the game we love.
So here is the breakdown on defensive schemes. I learned a lot; maybe you’ll find something you didn’t know in here too.
OCR (Oklahoma City Ram)
Cover 0 is a strict man-to-man alignment where each defensive back covers one receiver.
Cover 0 is an aggressive scheme that allows for numerous blitz packages, as it's easier for players to drop off their coverage and rush the quarterback.
The main disadvantage of Cover 0 is that there is no "help over the top" - if a wide receiver "beats" (runs past) his defender, there is no one left in the secondary who can make up the coverage on the receiver, which could result in an easy pass completion and possible touchdown.
Cover One is a man-to-man coverage for all the defensive backs except for one player (usually a safety) who is not assigned a man to cover but rather plays deep and reacts to the development of the play. Often the safety will remain in a pass coverage position and play a zone defense by guarding the middle of the secondary, reacting to runs or completed passes and double-teaming a receiver if needed.
In a traditional Cover 1, the free safety plays deep and all of the other defenders lock in man coverage to an assigned player for the duration of the play. Essentially, during the pre-snap read, each defender identifies the coverage responsibilities and does not change the assignment. Some teams play a variant of the Cover 1 called Cover 7. In Cover 7, the free safety still plays deep, but the underneath coverage is much more flexible and the defenders switch assignments as the play develops in an attempt to improve defensive positions to make a play on the ball. Examples of these switches include double covering a certain receiver and using defensive help to undercut a route to block a throwing lane.
Cover 1 schemes are usually very aggressive, preferring to proactively disrupt the offense by giving the quarterback little time to make a decision while collapsing the pocket quickly. This is the main advantage of Cover 1 schemes - the ability to blitz from various pre-snap formations while engaging in complex man-to-man coverage schemes post-snap. For example, a safety may blitz while a cornerback is locked in man coverage with a receiver. Or the cornerback may blitz with the safety rotating into man coverage on the receiver post-snap.
The main weakness of the Cover 1 scheme is that there is only one deep defender that must cover a large amount of field and provide help on any deep threats. Offenses can attack Cover 1 schemes by sending two receivers on deep routes, provided that the quarterback has enough time for his receivers to get open. The deep defender must decide which receiver to help out on, leaving the other in man coverage which may be a mismatch.
A secondary weakness is inherent in its design: the use of man coverage opens up yards after catch lanes. Man coverage is attacked by offenses in various ways that try to isolate their best athletes on defenders by passing them the ball quickly before the defender can react or designing plays that clear defenders from certain areas thus opening yards after catch lanes.
In traditional Cover 2 schemes, the free safety (FS) and strong safety (SS) have deep coverage responsibilities, each guarding half of the field.
The Tampa Bay Buccaneers, Minnesota Vikings, Chicago Bears, and Detroit Lions all run or have run a variant of this defense called the Tampa 2. In the Tampa 2 defense, a third player (usually the middle linebacker) plays a middle zone, guarding an area closer to the line of scrimmage than the safeties but farther out from typical "underneath" pass coverage’s. The Tampa 2 defense actually originated, at least in its earliest variant, with the Pittsburgh Steelers during the 1970s.
Cover 2 can be run from any seven-man defensive front such as the 3-4 and the 4-3 defenses. Various kinds of "underneath" coverage’s played by cornerbacks and linebackers may also be implemented. For example, "Cover 2 Man" means the two safeties have deep coverage responsibility while the cornerbacks and linebackers follow their offensive assignment in one-on-one coverage. The San Diego Chargers inherited a base Cover 2 Man 3-4 from former coach Wade Phillips. Cover 2 can also be paired with underneath zone schemes: "Cover 2 Zone" refers to two safeties with deep coverage responsibility, but now the cornerbacks and linebackers drop into specific coverage zones where they defend passes only in their assigned area.
In cover 2 the cornerbacks are considered to be "hard" corners, meaning that they have increased run stopping responsibilities and generally defend against shorter passes, although if two receivers run a deep route on a certain side of the field, that side's corner has deep coverage responsibility as well. It also relies heavily on the "Mike" (Middle) linebacker's ability to quickly drop deep downfield into pass coverage when he reads a pass.
A variant of cover two is the Inverted Cover 2, in which either right before or after the snap the corners "bail" out while the safeties come up - in effect switching responsibilities. This strategy may be employed to trick a quarterback who has not correctly interpreted the shift. However, the main drawback is that the middle of the field is left open.
The advantage of cover 2 is that it provides great versatility to the defense as the corners can play run, short pass, and deep pass with the confidence that they have support from two deep safeties.
The main weakness of the Cover 2 shell occurs in the middle of the field between the safeties. At the snap of the ball, many times the safeties will move toward the sidelines in order to cover any long passes to quick wide receivers. This movement creates a natural hole between the safeties that can be attacked. By sending a receiver (usually a tight end) into the hole, the offense forces the safety to make a decision: play the vulnerable hole in the middle of the field or help out on the wide receiver. The quarterback reads the safety's decision and decides on the best matchup (i.e. which mismatch is better: tight end vs. safety or wide receiver vs. cornerback).
Another disadvantage of Cover 2 is that it leaves only seven men in the "box" (the area near the ball at the snap) to defend against the run. In contrast Cover 1 and Cover 3 usually leave eight men in the box.
A potential problem with the Cover 2 is that defensive pressure on the Quarterback must be provided nearly exclusively by the front linemen as all other defenders are involved in pass coverage. If the defensive linemen do not provide adequate pressure on the Quarterback, the offense is afforded plenty of time to create and exploit passing opportunities. Blitzing in the Cover 2 often creates greater areas of weakness in the defense than other coverage’s. Thus, unsuccessful blitzes can prove to be more productive for the offense than in other schemes.
In cover 3, the two corners and free safety each have responsibility for a deep third of the field, while the strong safety plays like a linebacker. This coverage is generally considered to be a run stopping defense as it focuses on preventing big pass plays and stopping the run while giving up short passes.
On the snap, the CBs work for depth, backpedaling into their assigned zone. One safety moves toward the center of the field. The other safety is free to rotate into the flat area (about 2-4 yards beyond the line of scrimmage), provide pass coverage help, or blitz.
One of the biggest benefits of the cover 3 coverage scheme is the ability to walk the strong safety up into the box with minimal to no changes in the coverage due to the pre-snap center field position of the free safety. This enables the defense to play both man and zone coverage out of an 8 man front while cover 2 schemes allow only for man coverage with 7 man fronts.
Cover 3 schemes are susceptible to short, timed passes to the outside due to the hard drop of both cornerbacks. This puts pressure on the outside linebackers to react to pass plays and get into their drop quickly if they need to cover a receiver.
Another disadvantage of cover 3 schemes is they are relatively easy to diagnose by opposing quarterbacks. Because of this, teams will often employ slight wrinkles in their coverage to confuse offenses. An example of this includes employing man coverage on one side and zone on another or swapping coverage zones between defenders.
Cover 4 refers to four deep defenders, each guarding one-fourth of the deep zone. Cover 4 schemes are usually used to defend against deep passes or sometimes called prevent defense.
Types of prevent
The quarter defense has three down linemen, one linebacker, and seven defensive backs. The quarter defense gets its name as the next coin after nickel and dime in the sequence of defenses. Quarter or quarters can also be used to describe a type of zone pass coverage, in which four defensive backs divide the field into vertical quarters for zone coverage. This coverage may be combined with a 4-3 or 3-4, and is used to take away deep routes but maintain a good pass rush and run coverage.
(Half dollar defense)
Half dollar defenses have eight defensive backs and are very rare and are often used to prevent a Hail Mary pass. Professional teams may not have enough defensive backs on the roster to play the quarter or half dollar, so wide receivers are sometimes used to fill the extra positions, particularly in late game situations where the receiver's offensive skills can be put to good defensive use.
In this case the defense will pull back into what is called a soft zone. They will most likely play in a nickel, dime, or quarter package. A soft zone means that all the safeties and cornerbacks are playing back, five or ten yards off the line of scrimmage. The free safety will often play as much as 20 yards back. There will be no jamming of receivers on the line. The zone means that each defensive back is responsible for an area of the field, so they're all watching the quarterback's eyes instead of running stride for stride with a receiver. It is very easy for the offense to make short plays against this defense, gaining four to eight yards per play, but it's almost impossible for the offense to make a big play of 20 or more yards against this sort of defense.
In the fourth quarter when there are only a few minutes left in the game and one team is winning by 7 or more points, it's common in the NFL for that team to go into a "prevent" defense. In a prevent defense the idea is to make the other team use up a lot of time. The clock is stopped when the player with the ball steps out of bounds, so the first goal of the defense is to keep everyone in bounds. The only danger to the defense is giving up a big play, for example a 25 yard or longer pass or run. It doesn't matter to the defense if the other team makes a lot of plays, and gains four to eight yards per play, as long as the clock keeps running.
In Super Bowl XXXII, Denver Broncos coach Mike Shanahan famously instructed his defensive coordinators to keep playing the same defense as the Green Bay Packers attempted to drive downfield in the final two minutes of the game. The Denver defense managed to stop the Packers' drive, which led to the Broncos' 31-24 victory.
The Denver Broncos famously botched the prevent defense in the 2012 AFC Divisional Round playoff game against the Baltimore Ravens. With less than 40 seconds to play, the Ravens needed a touchdown to tie the game and faced a 3rd down from their own 30 yard line. Bronco’s safety Rahim Moore allowed Baltimore receiver Jacoby Jones to get between Moore and the end zone, where Jones caught a 70-yard touchdown pass from Ravens quarterback Joe Flacco. The Baltimore Ravens went on to win the game in double overtime, and eventually the Super Bowl.
The prevent defense is rarely used on consecutive downs, or with a significant amount of time remaining, since a team with time to move downfield would easily be able to gain plenty of intermediate yardage. John Madden once said, "All a prevent defense does is prevent you from winning."
The bend-but-not-break nature of the prevent defense tends to give the offensive team many easy gains but no big play, so the prevent defense can make the end of the game uninteresting for fans. Some coaches avoid using the prevent defense, choosing instead to continue playing the same defensive schemes that ostensibly gave them the lead to that point.
The most basic Cover 4 scheme involves two cornerbacks and two safeties. Upon snap, the cornerbacks work for depth, backpedaling into their assigned zone. Both safeties backpedal towards their assigned zone.
As with other coverage shells, Cover 4 is paired with underneath man or zone coverage in its most basic form.
The main advantage of a Cover 4 defense is that it is extremely difficult for even the best quarterbacks to complete long passes against it. Therefore, this coverage is generally used as a prevent defense to be used near the end of a game or half, meaning that the defense sacrifices the run and short pass to avoid giving up the big play with the confidence that the clock will soon expire.
Cover 4 also has the advantage of using safeties in run support as opposed to cornerbacks as would be the case in a Cover 2 scheme. This gives the defense nine in the box and the ability to stop the run with an extra defender on either side. The play-side safety would come up in support on a running play while the back-side safety would be responsible for the middle third of the field and the cornerbacks would have the deep outside thirds.
The main weakness of Cover 4 shells is the large amount of space left open by the retreating defensive backs. Since the defensive backs are working for depth, short pass routes underneath can enable the quarterback to make short- and medium- length passes, as well as isolate a defensive back on a wide receiver near the sideline with little help.
Cover 6 refers to three deep defenders. However, unlike the 'Cover 3', the field is not split equally. Most teams that use Cover 6 are 3-4 Defenses, call offensive strength to the Field instead of to the offensive formation or front, and organize personnel by Field-side player and Boundary-side player. The position of the ball on the field therefore dictates strength of the offense. In Cover 6 the field safety and field corner cover fourths of the field, and depend on a field outside linebacker to support underneath them. The free safety covers the boundary-side deep half and the boundary corner plays the flat. Thus the field side of the coverage is quarters, and the boundary side is cover 2.
The Cover 6 gets its name from the fact that it combines elements of the Cover 2 (the strong safety covering half the field) and the Cover 4 on the opposite side. The Pittsburgh Steelers are a Cover 6 team. The quarter’s play of the strong side safety, like the Steelers' Troy Polamalu, allows him to support on runs quickly. The Tennessee Titans have also been known to use it.
Cover 6 blends the best of Cover 2 and Cover 4. On the boundary, Cover 6 uses a Cover 2 corner. The boundary corner sits at 5-7 yards and is in excellent position to attack flat passes and wide runs, as well as blitz from a short field position. The boundary safety plays at 12-15 yards and supports the boundary corner, providing good pass defense over the top, as well as being able to assist on any vertical release by a 3rd receiver from the field side. The Field safety plays a hard read technique from 7-8 yards, reading first for run. He will fit hard and fast on run plays. He defends the pass by squatting or dropping over the #2 wide receiver. He will then play vertical patterns and in patterns by #2 then #1, passing off inside patterns. The Field corner plays a quarter’s deep coverage from 7-8 yards, reading the #1 wide receiver and playing all vertical and outside patterns.
Cover 6 has the disadvantages of both Cover 2 and Cover 4. The Field side is generally soft on flat coverage. The Field side corner can be left in single coverage deep as well. On runs, the field side may be spread by a tight end and 2 receiver formations, offering an advantage on the edge. The Boundary side is soft behind the corner to the sideline, as well as in the seam between corner and linebacker.