Heading into Week 5, the Steelers' defense is ranked second in yards allowed per game, points allowed per game, sacks and passing yards allowed per game. To put that in perspective, consider that in 2016, the only one of those categories where they finished within the NFL's top ten was sacks, where they placed ninth with 38.
The defense's significant improvement has resulted from a combination of the infusion of talented youth into the defense and the maturation of those players in Keith Butler's system.
Now the Steelers are starting to see each of those players mature not only into their roles, but how each of their roles interchange and work together in the various schemes Butler calls.
We take a look at how that worked in the Steelers' favor in their 26-9 victory over the Ravens on Sunday:
The key to being great in zone coverage schemes is being able to pass off receivers and maximize the use of space between each defender.
The Steelers have used zone concepts on defense because of the natural way each player in coverage can disguise what he is doing instead of having to line up over top of receivers in man coverage.
Knowing how your teammates' assignments work around you is vital if you're covering in a zone scheme. It's also vital to have an understanding of how opposing offenses operate and what parts of the field they like to attack with the various formations they use.
Through the first four games of the season, the Steelers' defense has shown that they are able to work together and close in on targeted receivers to tighten passing windows and force more accurate throws from quarterbacks.
A solid example came on a third-and-three opportunity for the Ravens early in the game.
WHAT'S WORKING
Joe Flacco dropped back and was looking for different routes the Ravens were running beyond the first down marker. The Steelers employed a Cover 6 defense with both Joe Haden and Sean Davis having deep-quarter responsibility on their side of the field while J.J. Wilcox had deep half responsibility to the other side.
The Ravens ran two slant-and-stop routes stacked on top of each other in order to try and get the Steelers' secondary to flinch and go after one of the routes, leaving the other option open as an easy target for Flacco.
Davis came up from his deep-quarter responsibility in order to help as soon as he recognized the pattern of the second slant-and-stop receiver (the receiver highlighted in red). He timed his advance almost perfectly and was able to jump in front of the target to swat the pass:
While you may think that Flacco just rushed his pass unnecessarily to his intended receiver Jeremy Maclin, take a look at the receiver highlighted in yellow. His route went behind Vince Williams and sat in the middle of the 40-yard-line.
But lurking next to Williams was the Steelers' star linebacker, Ryan Shazier, who was able to recognize that there was nobody he needed to cover in his space and turned back to help in the middle of the field.
If Flacco threw that pass to the middle of the field once that receiver sat, it would have needed to be a perfect floater because Shazier closed quickly on the space and could have made a play on that pass.
Another good example of this came when Mike Hilton dropped his first opportunity at an interception in the first quarter. The Steelers came out showing Cover 3 with Davis, Wilcox and William Gay all lining up to signify deep coverage.
Once the play developed, Gay (highlighted in red) vacated his apparent deep responsibilities and closed down on the receiver who passed Hilton. This made the play a Cover 2 defense instead of a Cover 3, which forced Flacco to process a different series of responsibilities than what he might have expected.
Flacco's only option on this third down would be to try and let his most highly decorated receiver, Maclin, be able to make a move against Shazier that might get him open:
Normally a receiver working against a linebacker would be an advantage to the offense, but Shazier stayed so close to Maclin that Flacco had to force a tight pass that ended up being high and almost intercepted.
Because Gay flew up to assist with the underneath coverage, the route behind Maclin was not available and Flacco's initial read had to change.
Forcing quarterbacks to flip between their options because the defense disguises its coverage is a key factor to putting offenses in position to make more mistakes.
While there was still a window for Flacco to hit his target, the point is for the defense to make the window as small as possible. The tighter the window each time, the more pressure on the quarterback to make consistent perfect throws.
If the defense can take the easy throws away, eventually that pressure builds up and leads to mistakes. Doing this consistently throughout a game takes a lot of coordination and communication between every player, as well as a developed understanding of how each player works together in the different schemes.
WHAT NEEDS WORK
The Steelers still do make mistakes in their understanding of coverage responsibilities from time to time. Spacing and reacting to different routes run by receivers leads to a lot of decisions from player to player. One misunderstanding can lead to the defense leaving a man wide open for the quarterback.
That happened when the Steelers sent Hilton in on a corner blitz and the Ravens ran a deep corner route with Maclin to the side the blitz came from.
Maclin is highlighted in purple and made his move right around the 10. Haden was playing that side of the field, but saw Breshad Perriman cutting underneath the defense and chased him.
This left that corner of the field vacant and needing a safety to help. Davis was the closest safety to that area, but he stayed toward the middle of the field to help against a simple streak by the tight end.
The only problem with that decision is that there was someone already covering that spot on the field. This led me to believe that with Davis being the only player running to cover somebody who was already accounted for, that it was his mistake in the coverage that opened up the opportunity for Maclin:
You don't see it from this camera angle, but Davis points over to Maclin after the play is over, signifying that he recognized why Maclin was so open. What saved the entire play was that Flacco started off looking to the side of the field where there were fewer defenders, but wasn't confident enough to test Artie Burns.
By the time Flacco was ready to look to his other options on the play, his pocket was crumbling and Hilton was able to bring him down for the sack. This was why he never saw Maclin.
The Steelers made a similar mistake on another play in the red zone. On that occasion, Flacco recognized it and just missed the throw. That play is broken down below.
The defense was in a Cover 3 scheme and the Ravens attacked it with a flood passing concept. The flood is a typical concept to use against Cover 3, because it forces certain players into tough decisions.
The Ravens had four passing options on this play to the right side of the field, but only three in this situation matter.
The first one to identify is the simplest. Mike Wallace (highlighted in sky blue) ran a go route against Haden (also in sky blue) to force his deep thirds coverage assignment to run into the end zone, clearing out the space underneath him.
The next offensive target to identify in this flood concept is the running back (highlighted in red) who attacked the flat and forced what is usually the lone defender playing the sideline underneath Haden's deep coverage to either come up to defend the flat or stay back in case the offense might have another receiver running a corner route to go over top of the flat.
Bud Dupree ended up being the defender to fill that space and properly took the flat as his primary responsibility.
Normally against a Cover 3 scheme that balances the coverage on both sides of the field, that would be enough to give the receiver running the corner route, Perriman in this situation (highlighted in yellow), free space to work his route and present Flacco with a solid target to hit.
That ended up happening, but the Steelers' defense was lined up in a position that should have prevented Perriman from ever being as open as he was on the play. Take a look at Davis (highlighted in yellow) and how he patrolled the space between Haden and Wilcox.
Both Haden and Wilcox had to stay deep to maintain their Cover 3 responsibilities, which left Davis with the choice of either guarding the seam, or helping out along the sidelines.
Davis ended up staying in the seam and coming up to help against a simple hook route where Williams was already working. This left two Steelers covering one target in their zone defense while leaving another to run free, a mistake that Flacco recognized but missed with his pass:
If Davis chased after Perriman on this play, Flacco would either try to force the pass into a very tight space and present a turnover opportunity or he would have to rotate back to his other options, giving the Steelers' pass rush more time to get after him.
It is worth noting that Davis being on this side of the field means that the defense recognized that the offense was coming with the flood option, but just that he most likely made the mistake in where he was needed.
While there were moments that Flacco missed on his throws, there were also quite a few passes that he fired with pinpoint accuracy into very small throwing windows presented by solid coverage from the Steelers.
Probably the best example of this was when the Ravens scored their only touchdown of the day. Flacco was able to recognize the Steelers' deep coverage responsibilities and attack them with a smash route concept.
Tight end Nick Boyle ran a short hitch pattern underneath Haden (highlighted in red) in order to distract him from helping in deep coverage just long enough. Wallace (highlighted in sky blue) ran a skinny corner route looking to get behind Haden, but also trying to keep Davis (highlighted in yellow) at bay long enough so that Flacco can fit the ball to him before either Davis or Haden can close.
Both defenders closed on the ball quickly, but Flacco threw the perfect pass to hit Wallace for the touchdown:
Despite the score, the Steelers' defense still did recognize what they were facing and forced Flacco to be great on this one play if he wanted to score. If both Haden and Davis were to see this passing concept again, they might jump all over it and even find a way to bait Flacco into a poor decision.
THE BEST EXECUTION
The defensive highlight of the day was Shazier's interception in the fourth quarter. While the result was great for the defense, the way they achieved it was a shining example of how good this defense can be when all of their players recognize their assignments.
The play for the Ravens is a play-action bootleg pass with two tight ends (highlighted in red during the play) releasing from the strong side of the formation and running crossing patterns back to the weak side of the defense. This kind of play has hurt the Steelers in the past as it is designed to take advantage of a team that flows with the ball to the strong side by freezing them with play action.
However, the Steelers reacted to every element of this play perfectly. It started with L.T. Walton (highlighted in red at the start of the play) staying disciplined in his responsibility for maintaining contain on his side of the field. Even though the offensive line had attacked away from him, he must be prepared for anything that might come back to his side.
When Flacco turned back from the other side of the line, Walton was not only waiting, but charging him. This forced Flacco to panic and try to hit one of his tight ends who would be attacking the weak part of the defense that they expected to be open.
But because Walton had lone contain duties on his side, both Shazier and Dupree (highlighted in yellow) were free to roam in coverage and look for where the Ravens wanted to attack.
Shazier started the play flowing with the play-action, but quickly turned around and ran with the real target, Benjamin Watson. Dupree was also turning to run with the tight end who was following Watson, showing that both players recognized their responsibilities.
The result is Shazier's interception and the Steelers getting the ball at midfield:
While this play focuses on the efforts of Walton, Shazier and Dupree, it's also worthy to look at how the other players on the field reacted.
Davis (highlighted in sky blue) was playing back in this coverage assignment and had the benefit of seeing everything develop. He pointed out what was happening right as the tight ends were about to turn into their breaks and communicated what he saw to the rest of the defense.
Williams also can be seen pointing on the play and most likely was an extra voice in calling out what the Ravens were doing.
Everyone did his job, and it allowed Shazier's athleticism to shine through as he made a key interception.
This is where the defense is headed if they continue to improve their communication and understanding of how to respond to the various formations they will face, as well as the different route concepts they will have to cover.
If communication like this continues, this unit could expect to keep that high ranking in passing and overall defense, and possibly even become the NFL's top-ranked defensive unit.
