The Pittsburgh Steelers parted ways with former long-time defensive coordinator Dick Lebeau at the conclusion of the 2014 season, thus opening the door for linebackers coach Keith Butler to take the reins of a group much in need of improvement. Butler and head coach Mike Tomlin have periodically employed a Cover-2 scheme in training camp and throughout the preseason in an attempt to rectify some of the issues facing a unit that ranked 18th overall in 2014.

Butler and Tomlin have used the team's four preseason games to experiment with the new Cover-2 scheme, and the results haven't been pretty. In four consecutive games, the Steelers' defense has surrendered touchdown receptions of 34, 31, 21 and 67 yards to opposing tight ends. This is especially worrisome for a defense that ranked 27th against the pass last season.

The key to the success of the Cover-2 is funneling the opposing offense's plays between the hash marks and rallying to the ball inside of a shell formed by the corners and safeties. Each defender must have his eyes on the quarterback at all times to react to a tipped pass, an underneath completion or a quarterback scramble. The diagram below illustrates the responsibilities of the linebackers, corners and safeties in a generic Cover-2 shell, with a 3-4 base front.

(Diagram from SB Nation's FieldGulls.com)

Let’s take a closer look at the responsibilities of each layer of the 3-4 base defense in the Cover 2.

SAFETIES (Shamarko Thomas, Mike Mitchell)

The success of the Cover-2 is predicated on having athletic safeties that can cover a lot of ground. The safeties start 12 to 14 yards off the line of scrimmage and split the field in half, vertically. On passing plays, the safeties drop back a few yards toward the sideline and they're responsible for the deepest receiver on their half of the field.

CORNERBACKS (Cortez Allen, William Gay)

The Cover-2 is designed to allow the defense to stop the run with only seven players in the box because the corners line up in either press coverage or about five yards off of the line of scrimmage. The corner must read the receiver. If the receiver breaks down to block, the corner must play with outside leverage so he can set the edge and turn the play to the inside.

On a passing play, the corner’s job is to redirect the route of the receiver to the inside. If the corner allows the receiver to beat him to the outside, it often leaves the safety with too much ground to cover. If the receiver breaks his route to the inside, then the corner has the opportunity to jump the route and go for the interception.

MACK LINEBACKER (Ryan Shazier)

The mack linebacker’s job is fairly simple. He drops about seven yards toward the hash mark and is responsible for anything that comes underneath.

BUCK LINEBACKER (Lawrence Timmons)

The buck linebacker drops about seven to ten yards into the center of the field. He is looking for anything that comes across the middle. In some situations, depending on the route of the tight end, the buck linebacker must drop deeper into the middle, and assume the role of a third safety. This variation is sometimes referred to as Tampa-2 defense, named after the Tampa Bay Buccaneers defenses of the late 1990’s and early 2000’s. Tomlin worked in the scheme as a defensive backs coach under head coach Tony Dungy.

SAM LINEBACKER (Arthur Moats )

The sam linebacker drops into coverage or rushes the quarterback.

WILL LINEBACKER (Jarvis Jones)

The will linebacker rushes the quarterback or drops into coverage.

The sam and will linebackers are playing what is called a "poaching zone." This means they are reading the quarterback’s eyes to decide if they need to drop on a route or pick up a player running laterally across the shallow middle.

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Now, let’s break down some of the long touchdown passes conceded by the Steelers' defense this preseason.

1st and 10 at PIT 34

Mike Kafka pass to MyCole Pruitt for 34 yards, TOUCHDOWN

Vikings-Steelers Preseason 2015

This play is a total disaster from the very beginning. The Vikings caught the Steelers in the wrong defense and took advantage by running tight end MyCole Pruitt, who had a free release from the line of scrimmage all the way across the middle of the zone.

Once Pruitt breaks his route to the left, corner Antwon Blake is left completely alone on the left side of the field, with nobody to cover. Ryan Shazier, the buck linebacker, and Shayon Green, the will linebacker, both decide to cover the running back in the flat, allowing Pruitt to get free behind the defense for an easy score.

Safety Ian Wild, who was cut by the team yesterday, runs with the slot receiver across the seam and completely abandons his half of the zone. If you stop the clip when Pruitt catches the ball, you can see Wild standing next to the free safety on the other side of the field.

1st and 10 at PIT 31

Chad Henne pass to Clay Harbor for 31 yards, TOUCHDOWN

On this play, safety Shamarko Thomas is cheating toward the middle of the field, and ends up covering the same zone as inside linebacker Sean Spence. This is a puzzling decision for the safety, as it appears Spence is maintaining nice coverage on his man.



Thomas is responsible for the deepest receiver on his side of the field, but doesn’t provide cornerback B.W. Webb with help over the top. In this instance, the deepest receiver is tight end Clay Harbor, who toasts cornerback Webb for an easy touchdown. In Webb’s defense, he probably let Harbor get behind him because he was anticipating help from the safety on the play.

1st and 10 at PIT 21

Scott Tolzien pass to Richard Rodgers for 21 yards, TOUCHDOWN

I’ve broken this play down into two parts. In the first clip, you can see Sean Spence, the mack linebacker on this play, making a shallow drop toward the hash marks, and maintaining coverage on the tight end running across his zone. The coverage by Spence isn’t great, as tight end Richard Rodgers is able to catch the pass in space. But once again, there is no safety help over the top.

The second clip shows Shamarko Thomas arriving on the scene just in time to watch Rodgers stumble into the end zone. You can’t see it in these clips, but Thomas bolts toward the sideline at the snap, once again abandoning his zone coverage responsibility.



Spence was visibly upset with Thomas after the play.

2nd and 13 at BUF 33

Pass from EJ Manuel to Charles Clay for 67 yards, TOUCHDOWN

The design of the defense on this play is head-scratching to say the least. At the snap, safeties Will Allen and Shamarko Thomas turn and run toward the sidelines, leaving the entire middle of the field open. Thomas and Mack linebacker Ryan Shazier slip, leaving buck linebacker Vince Williams one-on-one with Charles Clay, one of the most athletic tight ends in the NFL.

The three-man pass rush doesn’t get home, Williams doesn’t get enough depth, and the result is a 67-yard pitch and catch from quarterback EJ Manuel to Clay.

In conclusion...

The Steelers have the personnel to run the Cover-2 defense. Safeties Shamarko Thomas and Mike Mitchell are both fast and athletic, and are capable of covering large amounts of ground. Cornerbacks William Gay and Cortez Allen have the size and versatility to defend well against the run and the pass, and inside linebackers Ryan Shazier and Lawrence Timmons are as fast, physical and versatile as any duo in the NFL

Why then, have the Steelers defense given up so many big plays this preseason?

A lack of continuity and experience might be the primary reason. Mitchell and Timmons, two major pieces of the starting defense, have missed most of the preseason with nagging injuries. Per Mark Kaboly of the Pittsburgh Tribune-Review, the projected starting defense has only played together for an average of 7.2 snaps per game.

Perhaps another reason for unit’s struggles has been the inability to grasp the mental aspect of the scheme. Thomas, a first-year starter, has blown multiple coverages. Meanwhile, reserve inside linebackers Sean Spence and Vince Williams have had issues getting enough depth in covering the middle of the field.

There’s no telling how often the Steelers will run the Cover-2 defense in 2015. But for now, there’s no reason for Steelers Nation to panic. It’s going to take time for the defense to gel and learn the new system.

A lot of what we’ve seen during the preseason has been a product of Butler and Tomlin experimenting with new looks, deciding what they’ll keep and what they’ll scrap before the games actually count. There’s no doubt this defense will experience growing pains in 2015, but the talent is there and we should all be excited about what the future holds for the young group.