American Football - More Than Just The Basics (Defense)

In this continuing series of OLBG blogs aimed at helping increase knowledge of American Football and the NFL, I'm going to take a look at the defensive side of the game.

I will share some NFL tips and hints that can help with your understanding of how defenses work and how they are described during the game.

After checking my blog please visit the NFL Betting Advice Page. 

NFL Formations

You'll hear two basic descriptions of how a base (regular) defense lines up. 

These are the “4-3” and the “3-4”.

All the numbers refer to are the basic setup of the front seven in a defense. 

The first number refers to the number of defensive linemen a defense uses and the second number refers to the amount of linebackers.

So in a 4-3, you have four base lineman and 3 linebackers, in a 3-4 you have three base lineman and 4 linebackers.

The 4-3 is favoured by some teams as you have more big, strong lineman to match up against the offensive line. The linebackers are expected to be able to handle underneath coverage behind and clear up in the running game.

In a 3-4, the defensive lineman are often expected to tie up the blockers on the offensive line and let the linebackers clear up behind.

The Outside Linebackers are expected to bring an effective pass rush and consistently defend the edge of the formation. 

The Inside Linebackers are expected to do the dirty work of tackling and underneath coverage.

However, as discussed in previous blogs, offenses are much more pass-oriented nowadays so the base defense is used only about 40-50% of the time, as defenses have to adjust to what an offense is trying to do.

With this in mind, you'll hear the words “sub-package”, “Nickel” and “Dime” a lot. 

A sub-package is the team's alternative package of players to deal with passing formations. That sub-package will either be nickel or dime. 

A nickel is where one linebacker (or defensive lineman) is switched out for an extra defensive back, sometimes referred to as the nickelback. 

A Dime formation will see two linebackers or a combination of linebackers and linemen swapped out for two defensive backs with the second of those being referred to as the dimeback. 

You do get rare occasions where teams go with seven defensive backs and this is known as a Quarter defense.

It's also common for teams to use specialist defenders in obvious passing situations. 

Specialist pass rushers and nickel/dime linebackers will substitute in. 

A nickel/dime linebacker will sometimes actually be a safety and this is one of the recent trends of defense play.

Types Of NFL Coverage

You'll often hear about how defenses cover opposing receivers. 

There are two types of coverage. Man-to-man and zone.

Man-to-man is what it says on the tin. 

Each defender is given an opposing receiver to cover. 

He's expected to keep that receiver well enough covered that the Quarterback doesn't feel confident to throw it to him or if he does the defender can make a play.

 In Zone, a defender is expected to cover a certain area of the field.

So a cornerback will cover the outside edge of the defense. 

The Safeties will cover the deep half of one side of the field.

The linebackers will cover the short middle area.

Teams do mix up coverage sometimes, playing a combination of both, with the cornerbacks taking the receivers in man-to-man and all the other defenders in coverage playing zone.

NFL Blitzing

One of the best plays a defense can run is the “blitz”. 

All defenses have a natural advantage of one extra player as they don't have the ball.

Because of this they can use that extra defender to overload the offense and attack

A simple blitz is for 6 defenders to rush against 5 blocking offensive linemen. 

This will usually force the Quarterback to deliver the ball quicker than he's like and possibly make a mistake or if he can't find anyone open he'll be sacked by a rushing defender.

The danger of the blitz is it leaves single coverage behind it.

If the blitz fails to get home or the Quarterback beats it one mistake behind in coverage can be very costly.  

You'll see many variations of blitz which I won't go too deeply into here but you will see defenses use the threat of a blitz as a tactic too, often lining up like they are going to blitz but then backing off and going into coverage.

One thing that becomes apparent the more you watch American Football is how it is a game of cat and mouse, smoke, and mirrors. It's often a case of who can fool who.

Defensive Play Calling In The NFL

One last thing to add is how defenses call their plays.

Like an offense, they have a playbook with schemes and tactics they want to use. 

They'll be reacting to how an offense lines up so it's very common to see one of the Inside Linebackers (or Middle Linebacker in a 4-3 scheme) be referred to as the defensive signal-caller. 

A few seasons ago the NFL leveled the playing field for defenses allowing one of their players to also have a radio headset in their helmet just like an offense. 

The player wearing it will pass on the defensive coordinator's instructions, but he'll also make adjustments on the field as an offense maybe shifts its formation, or moves a player in motion.

Hopefully, these series of blogs have helped some of the more casual or newer fans of the sport. 

I'm looking to add a glossary of betting terms to a couple of blogs to give people something to refer to for this coming season.

As always, feedback and questions are welcome, either here or on the American Football Forum on OLBG. 

If you want to place virtual NFL Tips yourself please follow this link.

You can follow me on Twitter @ChrisJBrophy