Postgame Chalkboard: Gap Control

What a difference scheduling can make. One can make a solid case that last year’s North Carolina team played significantly better through the first two games than this version, but you wouldn’t know by the record. And in the final account, 2–0 is all that really matters

But that doesn’t mean there’s no reason for concern. After the Liberty game, I felt Carolina had played sloppy football but had flashed enough potential to give some reason for encouragement moving forward. This week, however, showed more significant weaknesses.

First on the list remains the lack of a vertical presence in the Tar Heel passing game. I said it last week, and I’ll say it again: If the Heels are going to win a division title in 2014, they’re going to need to threaten teams down the field better than they did against either Liberty or San Diego State.

This was thoroughly evident on Saturday, with the Tar Heel offense shut out in the first half and limited to seven points through three quarters—an offensive drought in which the Heels’ longest completion was 12 yards. (Yes, I know Ryan Switzer had a longer catch on a terrific throw from Marquise Williams that was inexplicably ruled an incompletion in the first quarter.)

That of course changed when Williams suddenly threw a strike on a deep post to Mack Hollins for a 91-yard score in the early fourth quarter—and Carolina not coincidentally scored ten more offensive points in the final frame than they had the other three quarters combined. Having a vertical threat changes everything in this offense, and Carolina has to find a way to manufacture more of it.

That said, the vertical passing game starts with good protection, and Carolina was all too often a hot mess trying to block SDSU’s exotic blitz packages when they did try to go downfield. Most of these protection problems boiled down to missed assignments (mostly due to poor communication and inexperience), something that will be more difficult to improve upon if Landon Turner’s injury keeps him out of action for an extended period of time. Carolina does have talented bodies up front, but they’ve got to grow up more quickly. My guess is that the SDSU tape will be especially valuable to that end.

I do have to give credit to the SDSU defense, which brought a very experienced front six into the game and had a great plan to bring confusion to Carolina’s young offensive line.

On the defensive side of the ball, missed assignments were a primary theme. The first Aztec touchdown was the result of a miscommunication in the secondary in which the corner and safety were playing two different coverages, leading to an easy 59-yard score.

But the bigger concern was in the Carolina run defense, which gave up 4.8 yards per carry on the day. To see why the Heels struggled to stop the run, we’ll look at Donnel Pumphrey’s 12-yard touchdown run in the second quarter.

This play is an example of the gap control issues Carolina struggled with all night. The run defense was solid when the defensive front stayed disciplined, but all too often (especially in the first half) the young defenders devolved into what coaches often call “hero ball,” trying to make plays rather than doing one’s job and relying on teammates to do the rest.

San Diego State runs a basic inside zone with reverse action on this play, while UNC is in a standard one-gap front, with each player responsible for a single gap in the running game (I’ve marked the assignments with arrows below).

The inside zone works off the displacement of the defensive front, aiming to get them moving laterally and cutting into a vacated gap. This version is especially designed to cut back against the grain of an overaggressive front, with the reverse action occupying end Mikey Bart, who is responsible for contain. That action allows the right tackle to combo block left defensive tackle Justin Thomason, who is responsible for the weakside B gap.

The offensive guard’s job is to help the tackle as long as needed to neutralize Thompson before moving to the second level to block linebacker Travis Hughes. Conversely, Thomason’s job against this play is to occupy his gap while keeping Hughes clean by preventing the guard from a clean release to the second level. In terms of technique, Thompson needs to squeeze the guard’s outside shoulder upon recognizing the inside step off the ball while not getting pushed too far inside by the tackle and creating an outside seam.

As you can see in the next shot, the offensive guard gets too clean a release to Hughes, and the tackle gets fairly square position on Thomason, who is beginning to get penetration but is in danger of getting squeezed out of his gap laterally.

The next frame shows the end result. Thomason has focused so much on getting penetration that he has allowed himself to get pushed too far inside, while the guard has locked onto Hughes. With Bart occupied by the reverse action, Pumphrey has a huge cutback lane.

Of course, with the reverse action occupying Bart, safety Tim Scott is now responsible to run the alley to clean up the cutback. Scott is late in his run support role, and Pumphrey gets the angle to make him miss, leading to the score.

This was terrifically schemed by SDSU to take advantage of UNC’s aggressiveness. To help prevent this, Thomason needed to better occupy the guard off the snap and then resist the lateral pressure from the offensive tackle to keep from penetrating himself out of his gap. The basic rule here is “fight pressure with pressure”—if the offensive lineman is pushing inside, the defensive lineman has to press outside and vice versa.

This is a difficult thing to learn for young players, as it’s natural to want to “whip your man.” But it’s far more important to maintain gap responsibility—it does no good to whip your man in the direction he wants you to go to begin with.

The good thing is that these are the sorts of problems that can be fixed. This Carolina defense is not as athletically limited as the past few years, and as these young, talented players learn how to play their roles, the defense still has a chance to be good moving forward.

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