The goal of every defensive game plan is to confuse and pressure the opposing team’s quarterback.
The most effective tool that a defensive coordinator can employ to achieve both of the aforementioned goals is the ‘blitz.’
If you watch a football game, you will hear the term ‘blitz’ thrown around rather often.
And while you may have a general understanding of the concept, you still have some questions.
In this article, I clearly define the ‘blitz,’ discuss its advantages and disadvantages and break down some of the most commonly used blitzes in football today.
- A blitz is when the defense sends at least five pass rushers at the quarterback to confuse, sack, or pressure him into making a mistake.
- A blitz may occur as part of a man-to-man defensive scheme or a zone defensive scheme.
- A blitz is a risky play for the defense. The more players that rush the quarterback, the fewer there are to shadow the receivers, increasing the likelihood of enormous yardage gains or scores.
What is a Blitz?
A blitz occurs when the defense sends five or more players to rush the quarterback to sack or pressure him into throwing an inaccurate pass.
While brilliant when properly executed, blitzes are considered risky because fewer players are available to cover the receivers when extra defenders are sent toward the quarterback.
Hence, if the blitz is appropriately picked up and the extra rushers do not pressure the quarterback, a poorly covered receiver may break free for a long gain or even a touchdown. 
There are two main classes of blitzes: zone and man-to-man.
However, to best explain what a blitz is, it would be helpful to explain what a blitz is not.
Under ordinary non-blitzing conditions, a defense will assign four players to rush the passer.
The picture below illustrates a non-blitzing defensive alignment. Note that there are only four rushers (identified in red rectangle) at the line of scrimmage :
Conventional or Man-To-Man Blitzes:
A man-to-man blitz is when five to nine defenders rush the passer, and any remaining defenders play man coverage.
The most aggressive and exciting blitz is the Cover-0 or Zero blitz.
A zero blitz is the riskiest call a defensive coordinator can make. It leaves no safety back deep, giving receivers one-on-one matchups across the field. The offense is scoring if a defender in coverage gets beat or misses a tackle. 
Every single DB is out on an island, and there is no deep safety help.
The zero blitz is just a numbers game. You are bringing more rushers mathematically than the offense can protect against and, as a result, are guaranteed to get a free rusher off the edge.
A great example of a zero blitz run to perfection by the New England Patriots in Super Bowl LIII – Patriots vs. Rams :
Notice that there is no safety help deep.
A zone blitz is when five defenders rush the passer, and the remaining six defenders play zone coverage. 
In deploying a zone blitz, there may be eight defenders at or near the line of scrimmage, giving the appearance of a zero blitz.
However, at the snap, only five of those defenders will rush the passer, while three will drop back into pass coverage.
For example, the following is an excellent example of a well-disguised zone blitz by the Arizona Cardinals against the Seattle Seahawks :
The key to any zone blitz is confusion.
Zone blitzes create:
- Confusion for the offensive lineman. Anyone can blitz or drop into coverage, and if the linemen don’t block the correct defenders, they may be relegated to bystanders, enabling free blitzes to pursue the quarterback.
- Confusion for quarterbacks. Defenders can pop up in places you weren’t expecting, leading to broken-up passes or interceptions. 
History of the Zone Blitz
While the fundamentals of the zone blitz were created by Miami Dolphins defensive coach Bill Arnsparger in 1971, the scheme did not gain widespread use in the NFL until Dick Lebeau refined it in the mid-1990s for the Pittsburgh Steelers. 
Lebeau told ESPN that he created the zone blitz out of necessity. Offenses began to exploit conventional blitzes with regularity, yet defenses still needed to pressure the quarterback. So Lebeau was looking at a less risky method to pressure the quarterback.
Lebeau’s zone blitz provided a means to get some pressure on the ball while playing some zone defense behind it. 
In this era of spread formations and pass-happy offenses, well-executed blitzes are not luxuries but necessities.
As this article lays out, defensive coordinators possess many options from which to choose.
- Recognizing Blitz & Pressure
- How the Dolphins Defense Cover Zero Shut Down Jared Goff | NFL Turning Point
- Steve Wilks’ Fire Zone Blitzes