Cal's Defense: Coverage and Pass Defense

Howdy all. We are just 8 days away from the Bears' season opener. I do not kid any of you when I say it gets increasingly difficult each night to fall asleep, being giddy with excitement.

But ignorance can make or break one's football experience! Educate yourselves on the game, so you don't find yourself unnecessarily upset! Angry because a DB got beaten on a route? Well does it make you feel better knowing that the DB actually never missed his assignment in the first place? Feeling like Dan Camporeale did nothing in run defense? What if you found out he did exactly what he was supposed to do on every play?

Here's your weekend homework. Read this third entry from Berk18 on Cal's Defense. This entry focuses on coverage and pass defense. If you haven't been following along, be sure to catch up by reading his first post on the basics of Clancy Pendergast's 3-4 and his subsequent post on defending the run game.

Seriously, do it. This is good stuff.

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In my last post, we saw how different coverages give players different responsibilities against the run. When most people hear “coverage” they think of pass defense though, and I'll look at the basics of that now.

When you're watching Cal, there are five basic coverages you should be able to identify: Man free, Cover-2, Cover-2 Man, Cover-3, and Cover 8. In this post, I'll show you how to identify each of those (some of them are pretty obvious), and what the responsibilities of the different players are in each of them. This will be the last post on the basics of defense. After this, I'll start putting some of what we've covered so far to work.

First up is Man Free, which is man coverage with an additional free safety (in the picture below it's Cattousse, the safety on the Cal 49 yard line). You can identify this coverage by the 1-high look of the safeties, with the second safety rotated down to cover somebody. In this particular picture Kendricks is blitzing the weakside A-gap, so Campbell is on the hashmark at the 47 yard line (just to the left of the ref), picking up his responsibility for any weakside receiver other than the split end.

The next key to recognizing man coverage of any kind (at least in Cal's defense) is that the CB's will generally be lined up heads-up over their receiver, and they'll be looking at the receiver instead of the QB. There are other kinds of soft man coverage where the CB's won't line up heads-up on their WR's (Cal will do this when the WR's are lined up in close to the line, for example), but Pendergast has his corners play aggressively whenever possible.

People teach man-free in different ways. For some coaches, the CB's are supposed to line up outside of the WR's and force them inside toward the free safety. In most cases for Cal, the CB's will let the WR get outside and then force him to the sidelines, as seen in Williams' coverage on this play:

Cal (like lots of teams) wants to take away the easy throws down the middle of the field first and foremost. Different teams prioritize this in different ways. Williams, by giving up the outside, puts himself in great position to defend any inside route, leaving the deep safety free to help on deep routes by a slot receiver or TE. The negative side of this strategy is that a WR who can use his space and leverage well, combined with a well-thrown ball, can lead to a big completion to the outside. Pendergast is often happy taking this gamble, because a lot of good QB's (like Barkley and Luck last year) miss this throw more often than they complete it.

I should comment more on the concept of leverage, which is really important in talking about and evaluating coverage. Except for sure-fire 1st round draft picks, you can't ask a guy to play inside his receiver AND to make plays on balls to the outside. On a play like the one above, it's inaccurate to say that Williams got burned (given that Richardson gained zero YAC). The coverage called for Williams to play with inside leverage and he got beat to the outside. Every coverage has a vulnerability, and this fade route is a vulnerability of man-free. If our CB's continuously get beat in this coverage on this route that's a failure of the DC to adjust. If the CB were to get beat to the inside on this play, however, that would be on the CB and not on the scheme, since the one thing a DB absolutely can't do is give up an inside pass when he's playing inside leverage, or an outside pass when he's playing outside.

The next coverage that Cal uses a lot is Cover-2 man (pictured below). In this coverage, we will have two safeties deep, each responsible for half of the field. Doing the math, a 4-man rush + 2 deep safeties leaves five defenders to cover five eligible receivers man-to-man, with safety help on anything deep:

This coverage can actually look a lot like Man-free pre-snap, which makes it a good switch-up with Man-free. If this were man-free, the CB's would be manned up on the outside receivers just as they are, the ILB's would be covering any back that releases to their side (which they can easily do from this alignment), and Cattousse would be covering the TE man-to-man. The way to tell that this is Cover-2 man instead of man-free is by the initial reaction of the safeties. Cattousse actually backs off more pre-snap, suggesting that he's not manned-up on the TE. Also, Campbell's first step after the snap is to the outside, showing that he's not responsible for the deep middle as he would be in man-free.

Since this is Cover-2 man, the coverage responsibilities for the backs and TE's would generally be sorted out post-snap with Camporeale, Holt, and Kendricks picking up the TE, H-Back, and RB based on the routes that they run (if they go into the pattern at all). So, Camporeale might cover whoever goes outside first (probably the H-Back), Holt might cover the first guy who goes vertical (in all probability the TE) or the second guy outside, and Kendricks is on the RB.

In any variant of Cover-2, unlike Man-Free, the CB's don't generally want to let the WR's get outside. The reason for this is that the major weak-spot in Cover-2 is the deep middle of the field. If the WR's get outside fast, the safeties have to widen with them and leave the middle of the field even more open. By playing with outside leverage and forcing the WR's back to the middle of the field, the CB's help make the middle of the field more congested and make it easier for the safeties to help everyone deep. The linebackers are trying to do the opposite to the TE's/backs/slot receivers, walling off anyone who tries to head quickly to the deep middle. With the CB's forcing the WR's inside and the LB's forcing everyone else outside, all deep receivers are forced straight to the safeties, who are then better able to assist on any and all deep routes.

Any man-coverage, whether you have zero, one, or two safeties deep, will be vulnerable to a similar set of routes and route combinations. Offensive coordinators know who likes to run a lot of man and who likes to run a lot of zone. If you run a lot of man, they'll use pick routes, shallow crosses, or anything that forces defenders to have to run through a lot of traffic. Whip routes, where a receiver breaks inside and then pivots 180 degrees in the opposite direction to the outside can also be tough because of the quick and drastic change of direction. Basically, any route that's designed to cause problems for someone that's chasing the WR can be used if the OC expects man-coverage.

To counter-act those kinds of routes, and to avoid predictability, DC's will also have a bunch of zone coverages in their defensive package. As a complement to Cover-2 man, there's plain Cover-2, which is a two-deep coverage with five underneath zones. We can see the difference between Cover-2 man and Cover-2 below.

This play was plain Cover-2. Something that Colorado likes to do from the above formation is to fake an outside zone run to the offense's left, while the left TE (flexed slightly off the left offensive tackle and off the line of scrimmage in the picture above) sneaks behind the line and releases into the flat to the right of the offensive line (this is pictured below). Meanwhile, the WR on the offense's right is running a corner route, pushing up field before breaking diagonally to the outside. The QB rolls right after the fake and has his choice, based on what the defense gives him, of the WR or TE. All of this is diagrammed like this:

Against man-coverage, it would be easy for the TE to get lost in the wash during the play-action. The WR at the top of the screen would be covered by the safety and the corner, and one of the linebackers would have to pick up the TE as he was sneaking behind the line of scrimmage.

Against Cover-2, however, this kind of mis-direction is no big deal:

The relevant zones are outlined in blue. Campbell and Cattousse are playing deep halves, with five underneath zones being played by the CB's and LB's. The TE is no longer a real threat, because his route is taking him straight into the LCB's zone.

As I said above, every coverage has a vulnerability. Against the plain Cover-2 pictured here, the corner route (the WR at the top of the screen) is actually really dangerous, since Cattousse will be defending an outside-breaking route with inside leverage and will have no help from the CB, who is playing an underneath zone. Fortunately on this play, the QB locked onto the TE, who had both Hill and Anthony around him) and then missed badly when he had to come off that and go to the WR.

The next zone coverage is Cover-3. As the name suggests, this coverage has three defenders playing deep 1/3's of the field, and 4 defenders playing underneath zones. The most typical Cover-3 look is called Cover-3 Sky, where the Sky designation tells you that a Safety is responsible for defending the strongside flat. This means that the weakside safety and both CB's will be the deep defenders. You can identify this by noticing that the SS is shallower than the CB's, as in the picture below:

In this picture, you can see that Anthony (bottom right corner), and Campbell (the shadow on the right edge) are already aligned deep, and Williams (toward the top of the screen) is backpedaling while Cattousse (outside of Camporeale and farther off the LOS, on the 17.5 yard line) is shallow and moving outside, so that he can cover the left flat. On this particular play, Davis (the ROLB) will be the 4th rusher, so the underneath defenders, from left to right, are Cattousse, Camporeale, Holt, and Kendricks. This zone coverage obviously makes it tough to pass deep, but does so by removing an underneath defender.

The last (and least aggressive) coverage that Cal uses is Cover-8. The pre-snap alignment for this coverage is pictured below:

This coverage is easily recognizable with its four deep defenders. It's often called Cover-8 because a lot of teams use Cover-4 to denote certain blitz coverages. Within this four deep shell you can play with either zone or man principles. Without seeing specific route combinations against this coverage, it's hard to tell which is being used. The assignments for Cover-8 zone are exactly what you'd expect, with the deep defenders each taking a quarter of the field and three zone defenders in underneath coverage. Cover-8 can also be played as a man coverage, but the assignments here are complicated and change according to formation and gameplan, so it isn't that useful to go into them here.

Each of these coverages has some adjustments that can look pretty exotic. For example, each of them has to adjust to slot formations, trips formations, formations with the WR's in tight, etc. Sometimes some kind of motion will happen and the coverage will change altogether. The ultimate way to ID the coverage is to look (1) at how many safeties are deep, as evidenced not just by their alignment but also by their initial movements after the snap, and (2) at whether the rest of the defenders are playing man or zone. If you can ID these five coverages, that'll go a long way toward figuring out who is supposed to be doing what, and toward deciding whether a completion is the result of a player failing to carry out his assignment or a result of the offensive coordinator outsmarting your DC. It should be noted that Cal runs plenty of other stuff as well. For example, there are combination coverages that might be zone on the strongside but man on the weakside, true double coverages, blitz coverages, versions of the above coverages where the safety rotation is to the weakside instead of the strongside, etc. We'll see some of these in later posts. If you can recognize the five coverages outlined in this post, though, that's a good start.

Now that we've seen the basic coverages, we can make some general comments on when Cal used them against Colorado. Man-free was easily the most versatile coverage, and we used it on all kinds of downs and distances. Cover-2 (usually man) was the mixer, presenting a different deep coverage shell and giving the CB's more help on deep routes. It's used as a mixer with Man-free especially on 1st downs, but is also often used as a counter to specific plays. Cover-3 was primarily used on more obvious passing downs like 1st and 15 or 2nd and 10, as well as being a zone coverage that could alternate with Man-free and various blitz coverages on 3rd down. Finally, Cover-8 was used when the offense had no choice but to throw deep, as well as near the goal line or at other times when we really want to defend a specific yard line. Against other teams, that distribution changed. Against ASU, for example, which is more of a constant 1-back offense with 3 or 4 guys split wide, we ran a lot more Cover-2 on 1st and 2nd down, including much more Cover-2 zone than we did against Colorado. It's all in the game-plan.