[Editor's Note: We continue on in our series of posts from Berk 18 on Cal's 3-4 Defense. If you haven't already checked out his first post with a general overview of Cal's 3-4 defense, do so now. It's seriously something every Cal football fan should read.
In my last post, we talked about fronts and how they work. In terms of the run game, the front is only half the story, though. The coverage that's called has a lot to do with stopping the run, so when you see a specific coverage you have to ask: What's the defensive coordinator trying to take away? Is he trying to stop a specific run or a specific pass? Is he looking for balance? There are a lot of factors that go into choosing a coverage.
To stick with the theme of run defense for now, let's talk about what has to be present on every run play. The front will account for all the gaps on a run between the tackles, but you also have to be able to defend outside runs. To do that, you want three people assigned to do three different jobs.
First, you need your primary support man. This player is aggressively engaging the lead blocker, and forcing a decision both by that blocker and by the back. The main goal is to get the ball-carrier cutting back toward the rest of your defense, or to string him out to the sidelines so that your guys have more time to react and swarm to the ball. You don't want him getting the edge or heading straight up field into a lot of space.
Inside the primary support man is the cut-back man. He's controlling the guy blocking him, staying on his feet, and 2-gapping (see previous post).
Finally, there's going to be a secondary support man, who's supposed to make the tackle when no one else does. You don't want your secondary support man making lots of tackles. Players at different positions can fulfill each of these roles, and who can do what is dictated by the front and the coverage.
Let's look at Cover-2 man to see this at work. In Cover-2 man your cornerback's lined up outside with their WR, and so they're in the best position to be the primary support man. We'll say that we're in “Corner Support.” In this support pattern, your strongside linebacker will be the cutback man. Your strong safety will be the secondary support man, playing the pass first but coming up in support if the WR on his side blocks. We can see this developing on a toss play on Colorado's first drive.
In this coverage, Anthony (bottom of the picture) has different responsibilities depending on whether the play is a run or a pass. If it's a pass, he's covering his WR man to man. If it's a run, this coverage calls for corner support, so he's the primary support man. He's going to be reading his WR, the TE, and the strongside back (the fullback in this case) to determine whether this is a run or a pass. Also, once other people diagnose what the play is they'll yell it out to the rest of the defense. Camporeale is going to be the cutback man, and Cattouse will be the secondary support.
Here's the picture as the toss is happening. Anthony's WR motions in closer to the line right before the snap. When this happens, Cal's going to drop their CB's off the line of scrimmage and a little outside the WR, so Anthony is the shadow in the lower righthand corner. His WR, #2, is cracking back on Camporeale, who's double teamed. Now that Anthony knows that it's a run, he's going to move into his role as primary support man.
Anthony (on the 34 yard line) engages the TE, who was coming out to block him. The RB has to cut back because of Anthony's position. The rest of the defense is in pursuit, and Kendricks makes the tackle. You can see that Cattouse is also up there in his role as secondary support man (a little above and to the right of Anthony in the picture, on the 36 yard line).
The support pattern is different for Cover-3, pictured above. In this coverage, the two corners and one safety are playing deep 1/3's. The other safety is responsible for defending the weakside flat (the short outside zone). In the picture above, Hill and Anthony are dropped off the line to defend their deep zones, and Campbell (the shadow toward the top of the screen) is playing the middle 1/3.
In this coverage Anthony is obviously not in position to be the primary support man, because he's worried about his deep responsibility first and foremost. This coverage calls for “safety support.” If this were an outside run, Cattouse (lined up to the ILBs' left, about 5 yards off the line of scrimmage)would be the primary support man, Camporeale would be the cutback man, and Anthony would be the secondary support.
One more thing to keep in mind is that your coverage determines how many players you have in the box to defend runs up the middle. If you're in Cover-2 or Quarters (a four-high coverage), it's harder to get a safety down into the box to defend the run since they both have deep responsibilities. If you're in Man Free (man coverage with a free safety deep) or Cover-3 you can bring your second safety into the box, giving you 8 men to defend runs up the middle as seen below.
This strategy isn't fool-proof, though. If the offensive formation is spread out in some way, the safety has to move out of the box to effectively cover his zone (or his man). This explains why Cattouse is out of the box in Image 4.
That's some of the most important information about coverage and the run game. In my next post we'll look at how different coverages defend the pass and take away certain plays.