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Football Film Study: Cal D vs. North Carolina

What worked and what didn’t in the season opener.

This off-season I’m going to take an in-depth look at the Wilcox/DeRuyter defensive collaboration. Throughout the next few months I’m planning to go through the entire season game by game, with a new post every two weeks. In these posts I’ll focus both on the trends that show up game-after-game, as well as on the gameplan-specific points that change from week to week. In this post I’m starting the series with the first game of the season against the North Carolina Tarheels. (Unfortunately I didn’t have time to make this a video breakdown, but hopefully I’ll be able to get back to that for the rest of these posts).

Cal Defense vs. UNC’s RPO Plays

In 2017, when you talk about defending the run game, you’re really talking about defending RPO’s (Run/Pass Options). While these plays were initially cutting-edge spread plays, it’s gotten to the point that just about everyone uses them in some form or another, from High School to the NFL.

UNC’s offense is pretty middle-of-the-road when it comes to RPO usage. They aren’t like the offenses that Cal fans have seen from Chip Kelly, Tony Franklin, or Noel Mazzone, where you can get four or five options on every play (including some downfield throws), but UNC will package most of their run plays with a backside screen, which makes them a pretty typical college offense and a great starting point for seeing how DeRuyter and Wilcox like to defend modern spread offenses. Here’s a skeletal look at an RPO that UNC ran a lot. It’s got a run to the right packaged with a Bubble Screen to the left:

This kind of play works best against split-safety zone coverages, like I’ve drawn up in the following diagram.

If the defense plays with this kind of split-safety coverage shell, then the offense can put the SOLB (highlighted in red) in a bind. The QB will just read that SOLB. If he creeps into the box to defend the run, as in the following diagram, then the QB will throw the screen. The outside WR will block the CB, and there’ll be no one left to make the tackle:

If, on the other hand, the SOLB widens with the screen, then the QB can hand the ball off with favorable numbers for the run:

In split-safety coverages like this, therefore, the SOLB can’t be right, because he has to play half in the run game and half in the screen game, and so he can’t do either of those jobs effectively.

DeRuyter and Wilcox avoided this problem by spinning down a safety for most of the game and playing with only a single-high safety:

When that SS rotates down, that lets him take responsibility for the screen, and allows the SOLB (still highlighted in red) to move into the box as a dedicated run defender. Single-high coverages like this, then, were our opening move in shutting down UNC’s offense, and in fact the Screen component of these RPO’s really wasn’t a factor for the entire game.

UNC’s Responses to this Strategy

Like every strategy, this one comes with a number of vulnerabilities, and one of the ways that UNC attacked it was with the Option. On this play, they leave that SOLB unblocked and the QB and RB attack him 2-on-1. The OL seal everyone else inside, and the WR’s block the CB and SS:

UNC scored two TD’s on this play in the Red Zone, and so this is something worth keeping an eye on. Playing this kind of defense might be good against RPO’s, but UNC had a good counter play to take advantage of this kind of coverage.

UNC was also able to attack this strategy by running to the right, or to the weak side of the formation. Let’s look back at how a split-safety coverage would line up against this kind of offensive formation:

We’re focused on the FS, whom I’ve highlighted. If you look at the offense’s formation here, you’ll see that they have three blockers to the right of Center (RG, RT, H-Back). This means that they can create four gaps (one between the C and RG, one between the RG and RT, one between the RT and H-back, and one outside the H-back). If the defense wants to fill all of those gaps, then they will need to get four players to the right side of the diagram. In a split-safety coverage this is relatively easy, because the FS is free to come down into the box once he reads run. When you spin to a single-high coverage, however, this changes:

With this safety rotation, the defense loses that FS to the right of Center. Now the offense has three blockers (RG, RT, H) to take on three defenders (DE, WILB, WOLB), which is a favorable matchup for them:

UNC took advantage of this numbers advantage frequently throughout the game, including on a 47-yard run that set up their first TD.

To sum the last two sections up, we’ve seen that from an X’s and O’s standpoint, the numbers weren’t always great for us in the run game. We were committed to playing mostly single-high coverages to eliminate the RPO’s, and this was effective, but it also made us vulnerable to some other types of runs. I would say that our front defenders, and especially our LB’s, out-executed UNC’s blockers and so were mostly able to make up for some of these numerical disadvantages; we were often able to contain UNC’s run game and to generate some TFL’s, even though we weren’t able to shut the run game down.

Defense vs. UNC’s Passing Game

In this game UNC’s passing game wasn’t very good, and it’s important to remember that they were platooning two new QB’s throughout the game. Our CB’s got beat on a few one-on-one slants and back-shoulder throws on the edge, but otherwise UNC wasn’t able to get much going. Throughout the game DeRuyter was mostly fine leaving CB’s alone on the WR’s and giving up a few completions here and there. The coverage inside, however, against short routes to the middle of the field, was much more interesting and yielded one of our two interceptions. To close out this discussion we’ll look at the scheme behind the INT. Here’s the pre-snap look:

Before the snap, it looks like the WOLB (highlighted in red) is lined up inside of his H receiver, which puts him in great position to cut off routes to the middle of the field. This is a pre-snap disguise, however, because that WOLB is actually blitzing on this play:

When the QB sees this blitz, he immediately throws hot to that H receiver on the slant:

This is a zone blitz, however, and so Davison (highlighted in Orange) is going to replace that blitzer and is going to step right in front of the throw, tipping it up for the Safety, who comes down with the INT:

In this way, DeRuyter used the blitzing WOLB (highlighted in red) to bait the QB into throwing this slant, and then replaced him with another LB to force the INT. This kind of thing happened throughout the game and took away one of UNC’s safety blankets in the short middle of the field.

Alright, that’s all I’ve got for today. Thanks for reading and be sure to check back in two weeks as I look at our defense against Weber State. Until then, Go Bears!