The start of fall practice marks the beginning of the 2012 season. One thing starts, another ends. Today's post on pass coverage completes my overview of Foster's defensive system.

First let's cover some basic, but unique terminology:

Boundary Corner: Cornerback playing to the short (boundary) side of the field. The boundary corner usually has more man responsibility, lines up in a press alignment (close to the wide receiver) and must be able to play zone with less safety help.

Field Corner: Cornerback playing to the wide side of the field. The field corner tends to play off the line of scrimmage (usually 7 yards off the ball, aligned even with the safeties).

Rover: In the old 4-4 defense the rover could line up all over the field, but most of the time opposite of the whip as a hybrid outside linebacker. As Tech's defense evolved, the rover essentially became a strong safety, most often lining up 7 yards deep to the strong side of the formation. The rover tends to be used more in blitzes, and in the past was usually the bigger, and better tackling safety.

Free safety: When the Hokies use two deep safeties the free also lines up 7 yards deep. You will also see the free safety line up ten yards deep in some change up looks. The free safety usually has the responsibility of calling the coverage and audibles for the secondary.

Foster's pass coverage schemes are predicated on getting turnovers as byproducts of the pressure generated through blitz schemes. Film review shows that the Hokies are much less dependant on straight man-to-man coverage than talking heads lead us to believe. However, every defensive coverage uses man-to-man principles which mandate that defensive backs have great functional football vision, hip flexibility, and explosion from a backpedal.

4-4 G Coverage (Cover 4)

The 4-4 G is Tech's base coverage, it's a cover 4 zone—the secondary is essentially split vertically into 4 quarters. In each zone, the assigned defender's goal is to not let a receiver behind him. When the Hokies play 4-4 G, the corners will either line up seven yards off the ball, even with the safeties, or they will line up in press, but backpedal immediately at the snap, or after the quarterback finishes his pre-snap reads. Initially the defender plays zone coverage, unless his cushion is threatened. The cushion is the space between a defender and receiver. The defender wants to turn and run without being burnt deep. While in coverage the defender is looking into the backfield, reading the quarterback's eyes. Once the cushion is threatened, the defensive back will turn and run with the receiver, just like in man coverage.

The 4-4 G is a "safe" coverage, but it still has an aggressive streak. Defensive backs often vacate their zones, especially on deep seam routes, because they determine that the quarterback will not throw in their zone.

On this play from the 2009 Peach Bowl, Tennessee sends numerous receivers deep on seam routes. Rock Carmichael recognizes that his deep quarter is not threatened and is watching Vols QB Jonathan Crompton the whole way. Crompton thinks he has man, and throws a deep ball anticipating that Kam Chancellor, who has his back to the QB, can't make a play.

0:16–0:34

Carmichael rolls and makes an easy interception. However, when you watch the play you will notice that the Vols have a wide open receiver in Carmichael's original zone (with Cody Grimm playing the short flat). Carmichael takes a risk to make a play, gambling that Crompton's eyes will take him to the ball. Note, top tier QB's can take advantage of this aggressiveness.

This is also a great example of a trademark of Tech's defense: the use of a robber in almost every zone or man look. Robber coverage is a term you will hear me use repeatedly during my film reviews this year. A "robber" means that in a coverage package, one player (it could be any defensive back, linebacker, or even defensive lineman who drops into coverage) is assigned to watch the quarterback and attempt to read where the throw is going. The robber does not have a zone responsibility, so he must be uber-aggressive and instinctual with a knack for making plays. Even in the wide-tackle six days, the robber was a key component in turning mistakes into turnovers. More often than not, when a defender intercepts a pass closer review will show him playing a robber coverage. The robber is a simple concept, but it is dangerous and difficult for a young quarterback to read because you can assign a robber in cover 1, cover 2, and cover 3 zones. Foster's defense will even allow quick underneath routes to be open in order to attempt to bait a quarterback into throwing to the robber on a quick read later in the game.

Cover 2 Robber

The standard cover 2 has two deep safeties, each responsible for covering a deep half of the field, with corners playing underneath zones. The Hokies use the robber to flip that look.

At the snap, both corners retreat from the line to play deep safety, or run with a receiver that goes on a deep route through their zone, while both safeties come forward to play short, wide zones. The safeties are in great position to intercept either a quick slant or seam as they come forward looking into the backfield. They are also in excellent position to support the run. The Hokies use this coverage less than in years past, but it continues to be their base look in clear run-support situations. It's weak if the opponents can send multiple receivers through a deep zone. Florida State absolutely torched the cover 2 robber in the 2002 Gator Bowl.

Cover 3 Zone with a Robber

In a standard cover 3 zone, teams will have three defensive backs drop deep with responsibility for a deep third of the field, while the linebackers and one defensive back play an umbrella of short zones. The Hokies will usually have their boundary corner show press coverage and then drop to a deep third, along with both safeties, while the field corner plays with his heels in the 7 to 10 yard range.

Quarterbacks seeing Cover 3 will look to make a quick throw, either on a seam to the back shoulder, or a quick curl in front of the retreating deep corner. The corner must be able to read the quick throw, plant, and fly forward to make a sure tackle, and if he reads screen or a quick throw to the flat, he must plant in his backpedal and fly forward to make the tackle. Once the QB becomes accustomed to throwing to that soft spot, Coach Gray throws in a robber coverage.

In the robber, 3 DBs will still drop into deep zones, but one player will aggressively read the QB's eyes and jump the route. Normally, safeties serve as the robbers, but Coach Gray's best corners, knowing that they have safety help, can also be used. The Hokies usually will run the Cover 3 robber with a lead at critical moments late in a game.

Here is a terrific example from the 2010 Miami game. Stephen Morris threw quick hot routes against Hokies cover 3 easily throughout the game. After the Hokies took a lead on Ryan Williams huge touchdown run, Miami found itself in a passing situation with a young QB.

Jayron Hosley is the robber on the play. He shows the Hokies standard cover 3 look, showing press and then almost peacock-like strutting backwards as Morris makes his pre-snap read. On the snap, the free safety rotates out to cover the boundary deep third. Jayron plants and is coming forward at the snap, looking directly at the QB expecting the quick throw to the Miami receiver, but he can take the risk because he has deep help. Jayron picks the pass off easily, and looks like Deion Sanders in the process, but the design of the defense, coupled with the repetition of the cover 3 look earlier baited Morris into the throw, which lead to the nail-in-the-coffin touchdown for the Hokies.

Cover 1 Robber and Zero Coverage (Straight Man-to-Man)

Cover 1 is man-to-man with a deep safety, while "zero coverage" is man-to-man across the field with no safety. The Hokies went through a period where they often "pressed" from zero coverage, meaning that the defensive back got right on the line of scrimmage, attempting to hold up the receiver within the 5 yard contact area and then turning to run over the top.

Recently the Hokies tend to only press when they play cover 1, with safety help. While this is safer, it is much more difficult to cover in man when the receiver has a free release from the line of scrimmage. Also, while 4-4 G can allow a cover guy to pass off a receiver to another defender, in man the Hokie defenders must follow their assignment all over the field, restricting their ability to read the quarterback or play in run support.

Still, special talents like Jayron Hosley make plays in man. Here, we have the Hokies in a cover 1 with Exum as the deep help (Whitley is near the line playing a spy on Denard Robinson).

7:01–7:11

Hosley is 7 yards deep at the snap (a standard Hokie look if they are not showing press) but it's man coverage. He reads the turn-in route and jumps in front of the Michigan receiver for a terrific interception.

I will admit, this was a challenging assignment for me. I have always been a lineman, but always wanted to be a receiver. Watching film for this piece has been a learning experience, and I am eager to learn more about alignment (why the standard 7 yard cushion?) and the fundamentals that Coach Gray and Coach Foster teach for reading keys and finding the football. Hopefully we will be able to explore this topic further as secondary play will be a key for the success of the Hokie defense this season.

This concludes my preseason look at the basics of the Hokie defense. Next week, I will overview the evolution of the Virginia Tech rushing offense from the early 90's until present day. After the August 18th scrimmage, I'll finish with a look at the identity of the 2012 offense. Thanks for reading! I'll answer any questions you have below.