Modeling Success: An Analysis of the Top Five NFL Defenses of 2012

Both the Eagles' offense and defense were awful in 2012, but there was a big difference between why each struggled. The offense failed because of turnovers and lack of depth - two issues that can be fixed (or at least patched) relatively quickly. The defense failed because of overrated starters, an uncommitted attitude and terrible chemistry, and a complete breakdown in coaching. These issues will take some time to fix (possibly multiple seasons), meaning that the defense is not going to turn the corner overnight like San Francisco or Denver.

But where to start? The days of having faith in coaches to implement a plan are long gone; if Kelly doesn't have some immediate success within his first two or three seasons he'll probably be canned. This includes improvement on both the offense and defense. He's tasked Bill Davis with tackling the latter problem and we all know that he prefers a "4-3 under" hybrid system that includes both 3-4 and 4-3 concepts. That picture is far too broad at the moment for the Eagles with all of their problems. If a scheme change is the only issue it implies that there is a decent base of talent already there on defense. The Eagles arguably do not have this overall foundation, so the roster must be the first thing evaluated before a system is even considered.

There may not be a better way to evaluate a roster than to see how it compares to NFL defenses that are already successful. In this post I'll look through the top five scoring defenses in the league last year and pick them apart to see if they had any similarities between either their system or talent base that might have contributed to their success. But to get an idea of what we have to work with, I'll start with the Eagles.

**Note: This information is meant to reflect the situation on defense for the following teams in the 2012 season. Any changes made since then may be reported in the "Commentary" section, depending upon its importance. The reported coverage schemes were found on an article at www.nflsfuture.com posted on March 28, 2012 and may therefore be outdated, even by 2012 standards. If you know of a more reliable source for coverage schemes that reflects the 2012 season do not hesitate to let me know in the comments and I'll correct this post.**

PHILADELPHIA

Defensive Coordinator: Juan Castillo, replaced by Todd Bowles
Base Formation: 4-3
Coverage Scheme: Zone
Scoring Defense: 27.8 points/game
Other Notes: Use of Wide 9 alignment and heavy defensive line rotation

Starting Lineup:
LDE Brandon Graham
LDT Cullen Jenkins
RDT Fletcher Cox
RDE Trent Cole
WLB Mychal Kendricks
MLB DeMeco Ryans
SLB Jamar Chaney
LCB Domonique Rodgers-Cromartie
RCB Nnamdi Asomugha
SCB Brandon Boykin
FS Nate Allen
SS Kurt Coleman

Commentary: It's a movie we've all seen before. This entire unit underperformed on a tragic scale, with only three players on the starting roster (Graham, Cox, and Ryans) playing at an average or above-average level. Jenkins has already been released and Mike Patterson was soon to follow. The entire secondary was atrocious, but there is some promising young talent on defense with Boykin, Kendricks, and Cox. Graham should continue to excel. Still, how much of this defense is torn apart is something that remains to be seen.

SEATTLE

Defensive Coordinator: Gus Bradley
Base Formation: 4-3
Coverage Scheme: Press Zone
Scoring Defense: 15.3 points/game
Other Notes: Regular use of 'hybrid' fronts that combined 4-3 and 3-4 looks

Starting Lineup:
LDE Red Bryant
LDT Alan Branch
RDT Brandon Mebane
RDE Bruce Irvin
LOLB Leroy Hill
MLB Bobby Wagner
ROLB K.J. Wright
LCB Richard Sherman
RCB Brandon Browner
SS Kam Chancellor
FS Earl Thomas

Commentary: The Seahawks' defense was nothing short of spectacular last year, with Gus Bradley's unit allowing just over two touchdowns per game. Of course Bradley is now the head coach of the Jaguars, but there is really no reason to see a decline in a unit that is loaded with great talent and good chemistry. The strength of the team was in their secondary which played at an extremely high level. Richard Sherman led the league with a ridiculous twenty-seven passes defensed while Brandon Browner finished tenth in Pro Football Focus' Yards Per Coverage Snap (YPCS) stat with 0.94. Safety Kam Chancellor racked up one hundred total tackles but was topped by linebackers K.J. Wright (112) and Bobby Wagner (157). Earl Thomas also managed to defend ten passes and intercept five more (plus two in the playoffs); he was only outdone by Sherman who picked off eight. On the defensive line, reach first-round pick Bruce Irvin excelled on third and fourth downs, where he finished seventh in Pass Rushing Productivity, per Pro Football Focus. Additionally, Brandon Mebane was eighth in the league in Run Stop Percentage at 9.7%.

Overall, Bradley managed to get great production out of his entire unit who played an extremely physical style of defense. By getting in the opponent's face, Gus crafted a defense that offenses really did not want to go up against.

SAN FRANCISCO

Defensive Coordinator: Vic Fangio
Base Formation: 3-4
Coverage Scheme: Zone
Scoring Defense: 17.1 points/game
Other Notes: Nothing minor; see commentary below

Starting Lineup:
LDT Ray MacDonald
NT Isaac Sopoaga
RDT Justin Smith
OLB Ahmad Brooks
ILB Navorro Bowman
ILB Patrick Willis
OLB Aldon Smith
LCB Carlos Rogers
RCB Tarell Brown
FS Dashon Goldson
SS Donte Whitner

Commentary: If the Seahawks have strength in their secondary, the 49ers have theirs in their linebackers. The unit performed exactly by design, with the outside linebackers excelling at rushing the passer while the inside linebackers plug up the middle. Both Aldon Smith and Ahmad Brooks finished in the top twenty of Pro Football Focus' Pass Rushing Productivity statistic (they finished with a score of 10.5 and 10.9 respectively). Smith was particularly effective on third and fourth down, where he tied for sixth in the league with five sacks. Meanwhile, NaVorro Bowman and Patrick Willis were tackling machines. Bowman amassed 163 tackles and Willis was not far behind with 149. Their secondary was not particularly outstanding but it's not like they were terrible either. In particular, nickel corner Chris Culliver (not listed above) led the league with a First Downs and Touchdowns Allowed rate of 3.45% per snap (courtesy of Pro Football Focus). Additionally, he tied for twelfth in the league in the YPCS statistic with a score of 0.95. It should be noted that the 49ers didn't enjoy the plethora of turnovers that they had in 2011, but they made them more by recovering fumbles than by intercepting passes. There wasn't much about the defensive line, but with all of the talent behind them they don't really need to do much more than delay the play for a few moments and let the linebackers and secondary clean up.

San Francisco was able to create a stout defense mostly by successfully executing the design of their system. They don't necessarily have the same flair that other defenses might have, but by acquiring talent at every level and playing hard as a team Vic Fangio has been able to make this once laughable unit very formidable.

CHICAGO

Defensive Coordinator: Rod Marinelli
Base Formation: 4-3
Coverage Scheme: Zone
Scoring Defense: 17.3 points/game
Other Notes: Use of "Tampa 2" defense; Marinelli has since been replaced by Mel Tucker

Starting Lineup:
LDE Corey Wootton
DT Henry Melton
NT Stephen Paea
RDE Julius Peppers
WLB Lance Briggs
MLB Brian Urlacher
SLB Nick Roach
LCB Tim Jennings
RCB Charles Tillman
SS Major Wright
FS Chris Conte

Commentary: It's probably worth mentioning that the Bears had a very roller-coaster 2012 and the majority of their stats were probably front-loaded in the first half of the season before the injury bug bit them. That being said, their defense was reliably good under Lovie Smith's tenure so their assortment of scheme and talent has been working. I'll start with the defensive line, where Henry Melton finished second in Pro Football Focus' Ron Stop Percentage stat (12.1%). Julius Peppers also tied for sixth in the league with five sacks on third or fourth down. In the linebackers, only Lance Briggs finished in the top twenty in tackling efficiency. The unit was not a dominant tackling team overall; Briggs led the team with 102 and only Charles Tillman had another respectable number with eighty-five. In terms of defending passes, the secondary was mostly average, but we all know what the Bears' bread and butter was: turnovers, turnovers, turnovers. It was almost unfair how often the Bears took the ball away; Tim Jennings and Major Wright had thirteen interceptions between them (Jennings had the lion's share with nine). A jaw-dropping four different players recovered two forced fumbles. Julius Peppers and Kelvin Hayden (not listed above) had four each.

Instead of taking the traditional path of defending their territory like the Seahawks and 49ers, Chicago simply just stole the rock from their opponent. And while they may have been deficient in tackling, their penchant for turnovers spoke for itself as they averaged out a little more than two touchdowns and a field goal allowed per game.

DENVER

Defensive Coordinator: Jack Del Rio
Base Formation: 4-3
Coverage Scheme: Man
Scoring Defense: 18.1 points/game
Other Notes: Nothing minor; see commentary below

Starting Lineup:
LDE Derek Wolfe
DT Kevin Vickerson
NT Justin Bannan
RDE Elvis Dumervil
SLB Von Miller
MLB Keith Brooking
WLB Wesley Woodyard
LCB Champ Bailey
RCB Chris Harris
SS Mike Adams
FS Rahim Moore

Commentary: The Broncos really made a team effort for their defense, but if there was any group that stood out it was their cornerbacks. Simply put, Champ Bailey and Chris Harris were outstanding - and you have to be to play corner in a man defense. Bailey and Harris graded out fourth and ninth, respectively, in Pro Football Focus' Yards Per Coverage Snap stat. They were also sixth and seventeenth (respectively) when it came to first downs and touchdowns allowed per snap. Their linebacking corps were versatile, with Von Miller leading the NFL in Pass Rushing Productivity (he scored a 15.7). Miller was particularly effective on third and fourth down, where he led the league in sacks (11) and finished second behind Cameron Wake in PRP. Wesley Woodyard led the team with three interceptions and 121 tackles. As you can also imagine from that statement, turnovers and tackling wasn't their strength, but it wasn't really a weakness either like it was for the Eagles. Both of their safeties registered over seventy-five total tackles, but for the most part the rest of the team "did their job." Rahim Moore finished ninth in the league in first downs and touchdowns allowed for safeties. Elvis Dumervil did grade out at nineteenth in pass-rushing productivity and Justin Bannan finished in the same rank for run stop percentage.

The Broncos had a great blend of excellent coverage, premium pass rushing, and a stout run defense. This combination of good fundamentals really made it difficult for opponents to plan for and gave Manning more breathing room than he probably had in his entire career in Indianapolis.

ATLANTA

Defensive Coordinator: Mike Nolan
Base Defense: 4-3
Coverage Scheme: Zone
Scoring Defense: 18.7 points/game
Other Notes: Some defensive success may be the result of the Falcons' high-octane offense; see full "Analysis" section below.

Starting Lineup:
LDE Kory Biermann
LDT Jonathan Babineaux
RDT Peria Jerry
RDE John Abraham
WLB Sean Weatherspoon
MLB Akeem Dent
SLB Stephen Nicholas
LCB Asante Samuel
RCB Dunta Robinson
SS William Moore
FS Thomas DeCoud

Commentary: Atlanta got good defensive play in the secondary, which complemented their quick-score offense well enough to earn them the first seed in the playoffs last season. Robert McClain (not listed above) was seventh in the league in Yards Per Coverage Snap category while our old friend Asante Samuel showed he is still a great cover corner. He ranked twentieth in Pro Football Focus' First Downs and Touchdowns Allowed per Snap statistic, was sixth in the league with twenty passes defensed, and cleaned up with five interceptions. Overall, the secondary picked off passes very efficiently with three of their members (DeCoud, Robinson, and Samuel) grabbing at least four passes each. Turnovers in general were a key theme for the Falcons' defense as they also had three defenders who recovered two fumbles each. This compensated for their average tackling; they only had four players with more than eighty tackles and Weatherspoon and Nicholas led the team with 108 and 103 tackles, respectively. Additionally, they weren't really able to rush the passer well. John Abraham (who is no longer with the team) is the only noteworthy player here since he finished sixteenth in Pass Rushing Productivity and was tenth on third and fourth downs.

The Falcons excelled on defense by complementing what they did well on offense. They may have gotten away with a bad run defense, but the turnovers they forced and the great secondary play certainly made up for those shortcomings.

Seattle Seahawks cornerback Richard Sherman (25) runs to the sideline with strong safety Kam Chancellor (31) and cornerback Brandon Browner (39) Credit: Daniel Shirey-USA TODAY Sports

ANALYSIS

Before diving deep into anything of importance, there are two things that need to be addressed. First and foremost, I realize that I only looked into things that the above teams did well and didn't bother to consider where individual players might have struggled. I did this on purpose since this post is an exercise on where good defenses excelled as opposed to their shortcomings. Secondly, there is an old saying that goes "correlation does not imply causation." I could spend all day picking apart arbitrary similarities in the above teams, but they might have no bearing at all on what makes an NFL defense successful.

With that in mind, I don't think the differences between safeties and cornerbacks can be ignored. For safeties, having at least one that is a sure tackler seemed to be vastly more valuable than having cover skills. Cornerbacks, for the most part, showed the opposite trend. This isn't to say those skills aren't important for those positions - ideally you want to have defenders at every level that can tackle and cover. But this is all about prioritizing those skill sets. Successful teams had corners with great ball skills while their safeties did most of the dirty work.

And if you think about it, this makes sense. Cornerbacks are really only isolated by themselves on streaks and fades. If the pass is completed the receiver is usually shoved out of bounds. For the most part, corners are getting help from linebackers on slant and drag routes and help from their safeties on posts. Of course, there is a difference between a great tackling corner and a physical corner. The Eagles' starters last year were neither of these, which led to their struggles. There is no real way to quantify how "physical" a corner is (except for possibly passes defensed), but I don't think anyone is arguing whether or not Richard Sherman, Brandon Browner, and Charles Tillman are physical.

Safeties, on the other hand, have responsibilities against the run and the pass and spend almost all of their time in the open field, meaning they have to be able to make open field tackles. This is run-of-the-mill common sense, but I find it interesting just how important tackling is when compared to coverage skills. Again, I'm not arguing against a ball-hawking safety, but it seems that skill takes a back seat to tackling ability.

Additionally, the dominance of zone coverage in the list is an important observation. This might be the result of the evolution of the game more than anything else. As football has become more popular, the better athletes want to play on offense, leaving a disconnect between the athleticism of receivers and the athleticism of defensive backs. Gone are the days where a good corner can line up against a good receiver all day long. With the exception of Darrelle Revis, the wide receiver (and increasingly, the tight end) will eventually win out. This became painfully apparent to the Broncos in the playoffs as Champ Bailey was consistently beat by Torrey Smith. Coincidentally, Denver is the only man coverage team on this list and the only playoff team to lose their first game in January.

The new breed of receivers in today's NFL makes the use of zone coverage much more advantageous over man coverage. When a receiver is being covered by multiple defenders throughout the course of a play it makes it harder for the offensive coordinator to create favorable matchups. This calls for more athletic defenders across the board, but it also simplifies each player's responsibilities and reduces the amount of time spent thinking during a play.

Another interesting trend was the overall lack of star power on the defensive line. With the exception of a few key players, no team had really anything dominant like the Giants' defensive line back in 2011 (or the Eagles' defensive line in 2011, for that matter). For all the talk about about succeeding on defense by bringing pressure with a ferocious defensive line, it is surprisingly absent from those teams. These defenses were still bringing pressure, but it was coming from other areas of the field. The defensive lines played adequately for the most part, serving as a stop-gap to create initial disruption in the play while the linebackers and secondary did the real damage. It might also be relevant to note that this was pretty much the opposite of Andy Reid's philosophy on defense, who stacked up talent on the defensive line but frustratingly ignored the decline of talent in the linebackers.

Finally, taking note of how these teams did offensively could provide some insight. Denver topped the list here with having the second overall scoring offense (30.1 points/game), followed by Atlanta (7th, 26.2 points/game), Seattle (9th, 25.8 points/game), San Francisco (11th, 24.8 points/game), and finally Chicago (16th, 23.4 points/game). There is a definite relationship between the performance on offense and defense with the most notable example here being Atlanta. The Falcons had a terrible run defense last season, but it often didn't matter because they were able to jump out to an early two-score league and force the opponent to abandon the run game early. Denver, on the other hand, was the opposite by doing most of their damage in the second half. Interestingly enough, all five teams on the list appeared in the top twelve for scoring in the fourth quarter. I don't think that this information has a lot of bearing on how the defenses may have performed overall, but it is certainly something worth considering.

Let's put all of this in context with the Eagles' moves in free agency. They've certainly done a lot with the intangibles by adding attitude on defense, especially in the secondary. Bradley Fletcher, as you've undoubtedly heard by now, certainly brings good ball skills to the table while Patrick Chung has proven to be an efficient safety in the box when healthy. Cary Williams does not have the proven coverage abilities that Fletcher has but his physical play is a good first step. Connor Barwin - a young linebacker with great upside - might end up being the defining acquisition as Howie moved to bolster the linebacking corps, something that the teams on this list show is pretty critical to success.

So, what does all of this mean? If you're not a stat junkie and don't really care for Pro Football Focus, then it won't mean much. I concede that numbers will never tell the whole story but I do think valuable insight can be had by examining them. Looking at the current state of the Eagles through the lens of the above teams and statistics, they've still got a lot of work to do. All of those teams primarily cultivated their defense through the draft and they all play with passion and attitude. A few players added in free agency can certainly bring passion and attitude given enough time in the locker room, and I think that's what the Eagles are going for more than anything else. Almost all of their signings play with ferocity and at least three (Barwin, Phillips, and Chung) have a chip on their shoulder after down years, injuries, and demotions. These are players who can instill a fresh culture into the locker room and help bring the real future of the defense into the league in a healthy environment. As far as talent goes, Kelly and Davis seem to be putting the team in the right direction if you model their moves after what made the five teams above successful. If Davis ends up not being the "guy," the Eagles will certainly have a defensive roster that better reflects a contemporary NFL defense for whoever takes over.

In the end, numbers and statistics are all speculation. No matter how much we analyze anything, we haven't really gained any new information. And it'll be like that until the team finally takes the field in September, which isn't getting here fast enough. But optimism is free and there's nothing wrong with doing a little searching for that light at the end of the tunnel.

(Sources: Pro Football Focus (http://www.profootballfocus.com); NFL.com (http://www.nfl.com); Team Rankings (http://www.teamrankings.com); NFL's Future (http://www.nflsfuture.com). All roster information was taken verbatim from each team's website. The exception here is Atlanta, whose roster was taken from ESPN.com (http://www.espn.go.com) since Atlanta had already updated their roster for 2013 Free Agency.)