When Jeremy Johnson takes his place behind center on September 5th, what will he be thinking? Will he continue the calm leadership example set by Nick "Shark Eyes" Marshall, or will the crowd and NFL venue get to him? Will he be determined to live up to Davey O'Brien Award hopes or will he be crushed by the pressure of SEC Championship expectations. Hopefully, he'll have the focus to instead be dissecting Louisville's defense like his coaches have taught him.

While coordinating offenses at Tulsa, Gus Malzahn taught his quarterbacks how to recognize eight basic coverages, each with their own strengths, weaknesses, and tells. The quarterback starts at the top of the defense and works his way down.

First, he looks at the safeties. Are there one or two safeties? How deep are they and how are they aligned with the receivers? Are they creeping toward a different position pre-snap?

Next, he looks at the corners. How far are they from the line of scrimmage? Are they playing straight ahead of the receivers or are they cheating inside or outside?

Finally he looks at the adjusters. These are the two players just outside the box on either side. They can be outside linebackers, nickel and dime backs, or even a safety in some cases. These players are responsible for run support and also rely on the corners and safeties for help in pass coverage, so their leverage on receivers can be telling.

After reading the defense, the quarterback should be able to determine the coverage and find mismatches or open zones. According to Malzahn, linebackers in man-to-man coverage is a mismatch in favor of the offense and there are four or five deep zones and seven short zones.

Here are the eight basic coverages for a quarterback to decipher. Warning: It's diagram heavy, but you can slide the viewer left or right to see each defense's strengths and weaknesses.

Cover 0

Structure/Technique

Cover 0 means there are no safeties deep. Each of the five eligible receivers is covered man to man, so that leaves six defenders to rush the pass.

Strengths

Man coverage prevents the defense from losing a receiver. It also prevents confusion as each defender should know who he has before the snap. With six possible pass rushers, the defensive coordinator can get creative with blitz packages. Plus, more players are close to the line of scrimmage, so this coverage is strong against the run.

Weaknesses

Sure, each defender knows who he's matched up with, but if just one defender blows his coverage or if just one receiver beats his man, there is no help coming. Each defensive back is "on an island" by himself. Linebackers are matched up with the offense's backs. In passing situations, this is usually to the offense's favor.

Indicators

Defenses usually disguise this coverage pretty well because a big play means a touchdown. It can't let the offense prepare. However, a safety might give it away when he comes down to cover a receiver. One, he can't cover deep, and two, the cornerback he's replacing is likely to blitz. Cover 0 is also likely if every defensive back takes an inside position on their receivers. With no help in the middle, each defender tries to force passing routes outside (more difficult passes) and toward the sideline (the best defender on the field).

Cover 1

Structure/Technique

Also known as Man-Free, Cover 1 has the free safety in a deep zone, but it is man to man everywhere else. This coverage also has a fifth defender available for rushing the pass.

Strengths

Like Cover 0, every eligible receiver is matched man to man, but the free safety in Cover 1 can provide help deep. The deep zone can be over the strong side, the weak side, or in dead center. Creative five-man blitzes are still available and plenty of players are in run-stopping position (just not as many as in Cover 0).

Weaknesses

This coverage still relies on linebackers to cover backs. Man to man defenders without the deep zone over top are still on their own. For example, if the free safety is playing in dead center, the two cornerbacks should expect no help.

Indicators

The adjusters (the will linebacker and strong safety) play outside leverage on receivers, hoping to funnel the routes inside toward the free safety's zone. The cornerbacks take an inside position on their receivers like in cover 0 as they are relying on the sideline to help them defend.

Cover 2 Man

Structure/Technique

Cover 2 Man also plays man coverage on all five eligible receivers, but it has both safeties in deep zones, one on each half of the field. The pass rush is left to the front four.

Strengths

Like the previous two coverages, every underneath defender is matched up with a receiver, but now there is deep help across the field. No defender is on an island. And with that help, corners can play with outside leverage, trying to force all receivers into more covered parts of the field.

Weaknesses

Linebackers are still responsible for backs, just like in the other man coverages. If the defense commits four players to rushing the pass, there is no one left to matchup with the quarterback. Therefore, quarterback runs and the option can hurt this coverage.

Indicators

There should be two high safeties if the defense is playing Cover 2 Man. With so much help deep, adjusters and corners can both play with outside leverage and push deep routes toward the safeties.

Cover 2

Structure/Technique

This is the first full zone coverage so far. Two safeties cover two deep zones while the other five defenders cover five underneath zones, corners in the flats, adjusters in the hook or curl zones, and the middle linebacker in the middle.

Strengths

Five of the seven underneath zones are covered, so the quick passing game isn't really a good option. A receiver running a deep route has to go through an underneath zone to get there and a good defender will force the receiver to alter his route or take extra time to get there.

Weaknesses

If three or four receivers can break through and get deep quickly, the two safeties won't be able to cover them all. There is an open throwing lane between the cornerback in the flat and the safety over top if a receiver can get there. Also, if the two safeties drift too far apart, a zone opens up the deep middle.

Indicators

Obviously, both safeties are still deep. Not as obviously, adjusters playing Cover 2 usually position themselves well inside of the slot receivers since the corner is covering the flat.

Cover 3

Structure/Technique

Another basic zone coverage, Cover 3 defends three deep zones, one in the middle by the free safety (like Cover 1) and two to either side by the corners. The other four defenders cover underneath zones, hook to curl by the middle linebackers, and curl to flat by the adjusters.

Strengths

With three deep zones covered, there is not much room for a pass downfield. Though there are fewer underneath defenders than in Cover 2, in Cover 3 they start closer to the box, so this coverage is better against the run.

Weaknesses

Only four of the seven underneath zones are defended. The offense has to be quick to the flat or precise between the middle linebacker and adjusters to hit the open ones, but they are open. A vertical route along the hash away from the free safety could come open as well.

Indicators

The free safety is centered and deep while the strong safety is closer to the box. The corners play off of their receivers because they will retreat to a deep zone after the snap.

Cover 3 Roll/Robber

Structure/Technique

Cover 3 Roll and Robber coverages are full zone coverages used to mimic other coverages while using pass rushers and zone defenders in unexpected places. For example, the strong safety can start up top (indicating Cover 2) but then fill an underneath zone while the rest of the secondary rotates or "rolls" to fill the deep void and play Cover 3. A robber is simply a player taking an underneath zone that wouldn't be expected to be there based on alignment.

This coverage is usually used with zone blitzes. If a defense sends five pass rushers, that only leaves six players in coverage to defend the rest of the field. An unexpected robber, or even a defensive end dropping into a zone, can diminish the offense's apparent advantage.

The image above is simply a Cover 3 defense disguised as Cover 2 pre-snap. Notice how the coverage rolls to the strong side.

Strengths

The main advantage is disguise. The offense might think the box looks favorable for a run, but after the snap, there will be an extra defender there. The offense might think there is no threat of a blitz, but this defense is designed to send unexpected pass rushers. And if the offense is expecting a blitz and hopes to throw where the extra pass rusher came from, the coverage is rotating to fill that void.

Weaknesses

The quick game outside is open because of the retreating corners, but it has to be noticed quickly. Also, despite three deep defenders, the vertical passing game is an option because the safeties are on the move and covering more ground.

Indicators

This coverage is difficult to see pre-snap because it is designed to disguise. There are likely two high safeties, but one of them might be creeping toward the box. The corners are playing off of the line since they have deep responsibilities. A defensive end planning on dropping into a zone might have a more upright stance than normal or some other tell. Regardless, it's important to notice Roll and Robber post-snap.

Cover 4

Structure/Technique

This coverage is a zone coverage that can adjust assignments on the fly. Each safety and corner is responsible for a deep quarter. (This coverage is sometimes called Quarters.) It sometimes looks like man when used against shorter routes like curls, but when a receiver runs deep and changes "lanes", the original defender can pass him off to the other zone's defender. The three linebackers stay in underneath zones.

Strengths

Four deep zones means nothing is going to work down the field. Plus, because the deep zones are so narrow, the deep defenders can actually cover more ground vertically, meaning they can help against the run. If the two safeties read run quickly, Cover 4 can present a nine-man box nearly impossible to run against.

Weaknesses

Cover 4 asks a lot of all defenders with reads and run/pass responsibilities, so there's a chance of a coverage breakdown. Play action can encourage such a breakdown. The real weakness, however, is that there are four open zones away from the linebackers underneath.

Indicators

This coverage is likely to be disguised as Cover 2, but the corners should be further back (like in Cover 3). The adjusters have a neutral or outside position over the slot receivers since there are no flat defenders.

Cover 42 (Cover 6)

Structure/Technique

When the strong side plays Cover 4 and the weak side plays Cover 2, it's called Cover 42. Swap those coverages and it's called Cover 24. They are both called Cover 6 elsewhere with no strong/weak designation (4+2=6). No, there aren't six deep defenders, only three, with two defenders taking a quarter of the field each (like Cover 4) and the third taking the remaining half (like Cover 2). Usually, quarters are to the field and halves are to the boundary. This allows the boundary linebacker to stay in the box since he has the corner's help outside.

Strengths

This coverage takes the strengths of Cover 4 and Cover 2 and applies them to one side of the field or the other. The strong safety can provide run support while also reading receiver routes. Therefore, deep passes to the quarters side are well defended.

To the halves side, the corner prevents any quick outside passes and also disrupts receivers trying to get downfield. Plus, the free safety provides deep help should the linebacker need help in coverage.

Some offenses call for a route combo to beat one coverage to the left and another route combo to beat another coverage to the right. This way, the quarterback can read a defense, eliminate one side of his offense, and focus on the progression to the other side. Cover 42 hinders this tactic by playing different coverages on each half of the field.

Weaknesses

Obviously, this coverage also takes the weaknesses of Cover 4 and Cover 2 and applies them to one side of the field or the other as well. To the quarters side, play action can affect quarter defenders' reads. There should also be open zones underneath to either side of the strong side linebacker.

The halves side is susceptible to multiple deep routes if they can get through the pressure underneath. There should be an open zone between the free safety and the sideline. If a wide receiver runs a crossing route from the quarters side to the halves side, he should find another open zone in between the safeties.

Indicators

To one side, the corner and safety are at roughly the same depth (indicating Cover 4). To the other side, the corner amd safety are at very different levels with the corner close to the line and the safety very deep (indicating Cover 2).

Make like a Cover 1 free safety and go deeper

Of course, defenses can incorporate countless wrinkles and adjustments to these basic coverages and offenses have to prepare for them as much as possible each week. But knowing these eight coverages gives the quarterback a foundation for finding the open man.

If you want to get a deeper understanding of each of these coverages and some of their adjustments, click the links below. Matt Bowen of Bleacher Report knows his defenses and, in my opinion, makes some of the most detailed, yet easy-to-read diagrams you'll find.

Cover 1

Cover 2 Man

Cover 2

Cover 3 (includes roll and robber versions)

Cover 4

Finally, I learned a lot from writing this post, but I know I'll forget it all in about a week, so I made a cheat sheet so I can quickly refresh my memory. You can use it too as we look into Auburn's passing plays and how they attack these defenses. View and download it here. By all means, if you think something is unclear, misleading, or just plain wrong, let me know and I'll take a look.