Stereotypical warning from author to readers: I'm not an expert. Blah blah blah. Read and rely on my statements below at your own risk.

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As a casual football fans, you'll sometimes hear the announcers talking about the "chess match" between a team's offensive coordinator and the opposing team's defensive coordinator. I'm sure most of us imagine both coaches expertly dissecting the unfolding plays with their eyes, contemplating what the opposing team is doing, looking down onto their offensive or defensive playsheet, and calling some other play in response to what just happened. The very next down, both teams line up against each other and execute another play. And another play. And another play.

To your casual fan, these are just plays, after plays, after plays. They may not seem all that different than each other. It may seem like nothing is really going on out there. In fact, it may seem like there is no "chess match" going on at all.

Is there a chess match going on?!?!

Absolutely. Let me try and illustrate it to you.

With every chess game there is an opening move. In our situation we are looking at the chess match between Oregon Head Coach Chip Kelly and Cal defensive coordinator Clancy Pendergast (I know Oregon's offensive coordinator is Mark Helfrich, but Oregon's current offense is Chip Kelly's child and I'm pretty sure he's the one calling the plays too). Therefore, the opening move is to be made by the offense.

THE OPENING MOVE BY CHIP KELLY

What is Chip Kelly's opening move?

It's the zone read.

No surprise there. The zone read -- and its many variants -- is the staple run play of the Oregon offense. I've already covered what the zone read is in the past so I won't do it again here. (Note: you can read about the zone read in some of my previous posts here, and here).

THE RESPONSE BY CLANCY PENDERGAST

Now, how does Cal's defensive coordinator Clancy Pendergast respond to Oregon and its zone read offense?

It's Cover Zero.

What is Cover Zero (Cal might call it "zero coverage"). It's a defense based on man to man principles. Every defender (more or less) has one offensive player to defend. It's a true 11 on 11 defense. Even the QB is covered by somebody -- typically, the QB is often not really covered by a defender. In most cases, a safety is the defender who is assigned the task of defending the QB.

Is Cover Zero a good defense to play against Oregon's offense? In my (amateur) opinion, yes. Why? As we saw in the 2009 Oregon vs. Cal game, playing zone coverage didn't really work so well. Oregon just flooded Cal's zones, and playactioned our poor linebackers to death. Zone defense is a rather reactive defense whereas Cover Zero is a more proactive defense. Cover Zero has strict assignments whereas zone defenses don't always have strict coverage assignments. With a Cover Zero defense, there should be absolutely no confusion as to which defender is covering which offensive player.

In my opinion, Clancy Pendergast's choice to defend against Oregon with Cover Zero was a great decision.

THE COUNTER-ATTACK BY CHIP KELLY

So Chip Kelly sees how Cal is defending against its offense. Now, Chip Kelly needs to counter-attack somehow.

How does he do it?

Watch the video below to see how Chip Kelly counter-attacks the Cover Zero defense (Special thanks to Avinash for providing the video):

Do you see it?

Okay, if you didn't see it, it's okay. It's a little hard to see. But let's dig into it and see EXACTLY what Oregon was trying to do.





Above is the pre-snap picture of the play. Oregon is in an 11 personnel set (1 back, 1 TE, 3 WRs) with a "trips" formation (3 WRs to one side of the offense). Cal is playing in its 3-3 nickel defense. If you watched the above video, you'll know that Oregon runs a zone read on this play.





What defense is Cal playing? We already know it's Cover Zero.

Let's quickly break down how we know it's Cover Zero.

On the trips side of the formation ("trips" means the side with 3 WRs), Cal is clearly playing man coverage. I've shown this with yellow lines connecting the DBs with the WRs that they are covering. How do we know it's man coverage? (1) Because all the CBs are to one side of the formation, as opposed to having a balanced defensive formation with a CB on each side of the defense. (2) The shallow depth of the CBs suggests man coverage. (3) Cal's middle slot DB is up close and personal with the middle slot WR and intends to jam him -- you typically don't jam on zone coverage. (4) the CBs are squared up on the WRs instead of playing outside leverage like Cal DBs do when playing zone.

On Cal's left side of the formation, Cal safety #11 (Cattouse), is lined up outside of the Oregon TE. This doesn't appear to be man coverage but it is. The reason why the safety is lined up on the outside of the TE is because the safety has outside-containment responsibility should this be a run play and the ball carrier bounces the ball to the outside. It's much easier to redirect the ball-carrier back towards the middle of the field by playing outside the blocker rather than heads up or inside the blocker. So even though the safety might not look like he's playing man coverage, he is.





What's the rest of the coverage? Well the rest of the coverage is merely Cal safety #17 (Conte). What is he doing? He's playing the QB.

How do we know this? We look at his alignment. I've drawn a long yellow line down the middle of the field from where the QB stands. I've also drawn a shorter line from Conte's feet over to the division line. Conte is playing to the defense's left. This is significant for a few reasons. First, if Cal was playing Cover-1 (one deep safety), then Conte would be aligned either in the middle of the field or more towards the trips formation on the defense's *right* side. But Conte is on the defense's *left* side. He's on the left side because his job is to guard the QB on a zone read play if the QB keeps the ball. And on a zone read play, the QB will always run to the side of the field that the RB is on. Since the Oregon RB is on the defense's left side, Conte can expect the QB to run to the defense's left side.





So clearly, Cal safety #17 (Conte) is playing the QB.





Putting all the coverages together, what do we get? We get Cover Zero. Cal is playing an aggressive man defense with absolutely zero deep safety help (because both of the safeties are assigned to cover specific offensive players rather than sitting back in deep coverage).





So now let's move on to the actual play itself. Oregon starts off putting the inner-most slot player into motion across the formation.

Here's the field just as the QB and the RB are meshing. The responsibility of the motion man is to block the defender who was covering him. Seems obvious enough, right?





Here's the not-so-obvious part. Oregon's TE is going to block Cal safety #17 (Conte), instead of blocking the Cal safety #11 (Cattouse) who is right across from him.

What's going on here? Why doesn't the Oregon TE just block Cal safety #11 (Cattouse) right in front of him? After all, Cal safety #11 (Cattouse) is covering the Oregon TE, so it makes sense that the TE just block the defender guarding him, right?

Not quite.

To explain, I turn to my crappy photoshop drawings in an attempt to illustrate.





So above, I've shown the formation from the offense's point of view.





The defense, as we know, is playing Cover Zero. That means the FS (Conte) is covering the QB, and the SS (Cattouse) is covering the Oregon TE. I've shown these coverage responsibilities with blue lines.





Oregon will have its TE block the Cal FS (Conte). Remember, the Cal FS has the responsibility of defending against a QB run. So what happens if the TE blocks the FS???

NOBODY WILL BE COVERING THE QB.

This is EXACTLY what Oregon wants.





Remember, Cal SS #11 (Cattouse) is covering the Oregon TE. Cattouse doesn't know that the TE is going to block Cal S#17 (Conte). Cattouse just thinks the TE is running a route, and it's Cattouse's responsibility to cover that route so he drops back into coverage and away from the line of scrimmage. I've shown this with a yellow line above.

This, of course, is exactly what Oregon wants. They are HOPING that the person covering the TE (Cattouse) doesn't realize what's going on and drops back into coverage. Because essentially then, that one TE is taking out two defenders (by blocking Conte, and having Cattouse follow him) .

That last sentence is so important, I want to say it again: that one TE is taking out two defenders (by blocking the Conte, and having Cattouse follow him) .

Remember, Cover Zero is a defense based on man coverage principles. It's a true 11 on 11 defense where every since defender has their own offensive player to cover/block.

Since Oregon had its TE block the FS (Conte), and the SS is also covering the TE, the effect is that the defense basically has two defenders occupied by one offensive player .

In other words, instead of being 11 on 11. All of a sudden, the play is now 10 defenders vs. 11 offensive players. The defense is now down one defender.

So what has to happen on defense for them not to be taken advantage of by this nifty trick by Chip Kelly?

The SS (Cattouse) has to be aware of the situation, and realize that the TE is going to block FS (Conte), and thus he (the SS) and the FS have to basically swap responsibilities . In other words, no longer is the FS covering the QB, but the SS is now covering the QB instead.

Let's go back to the play and see how it unfolds...





Going back to the play, we can see the Oregon TE trying to get to Cal FS #17 (Conte) shown by the yellow vision cone. Unfortunately for him, his efforts are hampered by the fact that the Cal SS #11 has recognized the run play and is engaging the TE to stop the run.





And here's where it gets more obvious that the TE is really trying to block the FS instead of the SS in front of him. Here you can clearly see the TE lining up his sights on the FS (Conte).





And BOOM. The money shot. The Oregon TE smashes the Cal FS (Conte) breaking the FS's coverage (broken red line). Fortunately, Cal's SS #11 (Cattouse) saw that the QB kept the ball on the zone read and has basically taken over the coverage responsibility of the FS (shown with a yellow line).

Watch this play again, now that you know what Oregon is trying to do. Specifically, watch that Oregon TE on the end of the LOS as he attempts to work his way to the Cal FS but is hampered due to the Cal SS:

Pretty cool, huh?

Oregon chooses to block their zone reads like this on purpose because they know that a lot of teams will play Cover Zero against them.

I must note that this isn't the cleanest play to choose to illustrate what Oregon is trying to do. I'm sorry. Cal's SS #11 (Cattouse) does a great job stymieing the efforts of the Oregon TE in blocking the FS (Conte). But I chose this play for that very fact. Cattouse, whether because he knew what Oregon was doing (very likely), or because he was just so concerned about the QB keeper on the zone read (as he should be) was very quick to attack the run and get in the way of the Oregon TE.

Let's watch another play. In the play below, you'll see Oregon do the same thing, but this time instead of using a TE to block the FS (Conte), they'll use a WR.

(Hint: the WR who blocks the FS (Conte) is at the bottom of the screen).

Did you see it? The Oregon WR at the bottom of the screen bee lines towards Cal FS #17 (Conte) to take him out. Unfortunately for the Oregon WR, a few things go wrong. First of all, Cal CB #1 (Williams) gets in the way of a clear path to Cal FS #17 (Conte). Second, the Oregon WR doesn't even really get a hand on Cal FS #17 (Conte) although you can see the Oregon WR desperate trying to grab Cal FS #17 (Conte) as he runs by. Nevertheless, the Oregon WR slows down the FS enough to allow the Oregon QB to get the first down, but he (the Oregon WR) also draws Cal cornerback #1 (Williams) far enough off the line of scrimmage to create a void of defenders to stop the QB run.

That's the whole one offensive player occupying two defenders concept .

Remember, a Cover Zero defense hopes to have the following match-ups which results in 11 defenders vs. 11 offensive players:

5 Offensive Linemen + 1 Runningback = 3 Defensive Linemen + 3 Linebackers

3 WRs = 3 CBs

1 TE = 1 SS

1 QB = 1 FS

As you can see, all 11 offensive players are defended by a defensive player.

But since Oregon is using a TE (or WR) to occupy both a CB/SS and the FS, the following match-ups result:

5 Offensive Linemen + 1 Runningback = 3 Defensive Linemen + 3 Linebackers

3 WRs = 3 CBs

1 TE = 1 SS + 1 FS

1 QB = [no defender]

Here, 11 defenders are only covering 10 offensive players. That's what Oregon is trying to accomplish.

Conclusion:

Let's recap:

Chip Kelly's opening move: Zone read

Clancy Pendergast's response: Cover Zero

Chip Kelly's counter-attack: blocking the FS with either a TE or WR

There is your chess match. It does exist. It is happening. It's always happening even though the plays which are unfolding before your eyes look no different than before.

Now, the final question which is probably on your mind is: "What can the defense do to counter the offense's attempts to block the FS?"

I'm no expert, but my answer to this question is to have the SS/CB (whomever is covering the TE or WR who is attempting to block the FS) swap coverage responsibilities with the FS. In other words, the FS will now cover the TE/WR who is attempting to block him, and the SS/CB whom would originally be covering the TE/WR is now instead covering the QB. This solves the problem of the offense gaining the 11 vs. 10 advantage.

I've drawn out a picture below:





Remember, originally, the FS would cover the QB, and the SS would cover the TE (shown with the blue lines connecting these players). If the defense just swaps the coverage of the FS and the SS, so that the FS is covering the TE, and the SS is covering the QB (shown with the gold colored lines), then the problem of gaining an 11 vs. 10 advantage is solved.

However, this hypothetical defense poses two problems. First, you have to teach your defenders to recognize which of the offense's players is going to block the FS. This isn't entirely hard to do though. Oregon either does it with the TE, or the outer-most WR to the backside of the zone read (the side the QB will run to if he keeps the ball). So the issue just becomes a matter of drilling your defenders into quickly recognizing who that player is. The second problem, is that now the defense has a SS/CB covering the QB, and a FS covering a TE/WR. The SS/CB will be out of position to cover the QB as since the SS/CB will most likely be aligned more to the outside rather than directly up-field from the QB (allowing the QB easier running lanes up-field and to the opposite side of the field). Also, the FS covering a WR a somewhat bad combination too as since the FS will also be out of position and isn't as great as a pass defender as a CB.

And let's just suppose that Cal started playing this hypothetical defense. What does Chip Kelly do in response? Easy. Just run QB-keepers to the opposite side of the SS (the defender who is covering the QB) and use the RB as a lead-blocker. So simple.

So there are counters for everything. Some counters work better than others. Some counters can be nullified with better execution.

Football, despite the never-ending schematic "chess match" which is going on, is also decided by execution (which includes talent). During this particular game, I think Chip Kelly very slightly out-schemed Clancy Pendergast. But it was Oregon's better execution and talent level which ultimately led them to win the game.