The success of the 2016 Eagles will have to rest on a defense that already seems to have all the pieces in place, and a new defensive coordinator in Jim Schwartz who understands how to find success.

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In 2015, the Eagles’ defense featured a number of high-performing players—from linemen Brandon Graham, Bennie Logan and Fletcher Cox to linebackers Connor Barwin and Jordan Hicks to cornerback Nolan Carroll and hybrid safety Malcolm Jenkins. The team had more than enough talent on that side of the ball to produce strong results, but that’s far from what happened.

Last season, Philadelphia ranked 28th in points allowed, and 30th in yards allowed. Only the Saints allowed more passing touchdowns than the Eagles’ 36, and Philly allowed the league’s most rushing yards with 2,153. The personnel decisions and high-tempo offense of now-deposed coach Chip Kelly had something to do with that—hurry-up offenses tend to lead to tired defenses—but there was still enough defensive talent on the field. There was another issue for the Eagles.

Defensive coordinator Bill Davis, in his third season with the team, had created a set of schemes that forced linemen and pass-rushers to focus too intently on their assignments at times when the better option would be to cut loose. And the alarmingly high number of coverage breakdowns indicated that what Davis was drawing up for his pass defenders wasn’t working at all. Davis preferred a strain of the 3–4 hybrid defense that is currently all the rage, but he was never able to put his estimable roster talent to its best use, and as a result, the Eagles fell from 17th to 29th in points allowed in Davis’s three-year term.

When Kelly departed, general manager Howie Roseman swept Davis out the door and replaced him with Jim Schwartz, who was last seen turning the Bills’ defense into a true force in 2014. That season, Schwartz schemed a defense that ranked fourth in yards allowed and scoring defense, third in takeaways with 30 and first in sacks with 54—quite an improvement from the work Mike Pettine did as Buffalo’s defensive coordinator the year before, and Rex Ryan and Dennis Thurman didn’t come close to matching it in 2015.

Schwartz prefers the “wide-nine” defense—tackles gapping on the guard and center, and the ends splayed wide in a four-man front to create advantage against potential double-teams. That’s a decent thumbnail, but in truth, Schwartz has many different things he likes to call based on personnel and situation. He’s just as likely to call his ends in and move the tackles outside the guards, and he has several different pressure packages—end-tackle stunts, linebacker and safety blitzes, and so forth.

On obvious passing downs, you may see three-man fronts with nickel coverage behind and a tackle at linebacker depth (this was a favorite of his during the Ndamukong Suh era in Detroit). Schwartz needs his linebackers to be heady and diverse, and he prefers aggressive man coverage, though he’s also highly effective at calling zone coverages. As a defensive play-caller, he’s always been very adept at aligning his personnel to situational football.

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So, how does the Eagles’ current defensive personnel fit into that structure? Most of the players seem happy with the switch, and it’s easy to see why. Cox is one of the best multi-gap players in the league—he can play anywhere from end to straight up nose tackle and dominate—but his base position will likely be three-tech in this scheme. And as a one-gap inside penetrator, he has the attributes to be an absolute terror. Logan would ostensibly be the one-tech, the guy responsible more for stopping inside runs and soaking up blocks.

At end, there are a lot of options. Graham is a perfect fit, as is the underrated and underutilized Vinny Curry. Barwin may see some situational time as a pass-rushing end, but Schwartz is too smart of a coach to avoid taking full advantage of Barwin's positional versatility.

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Nolan Carroll and LeodisMcKelvin are the most likely starters at cornerback—Schwartz had McKelvin in Buffalo—while Jenkins and former Rams standout Rodney McLeod are likely to play a ton of reps at safety. Schwartz has been particularly complimentary of Jenkins and McLeod as a dynamic safety tandem, though Jenkins really broke out last season as a multi-position defensive back, proving he’s able to play safety and slot cornerback with equal aplomb. Eric Rowe, along with rookies Blake Countess and Jalen Mills, may be factors throughout the season.

Schwartz has plenty work with here, and while one never knows for certain who may line up where, one thing is for sure: In today's NFL, it’s crucial to have as many DB options as possible, especially with players who have the ability to shine in more than one role.

“If you have a safety that's not comfortable playing out there like a corner, you're going to be in trouble,” Schwartz recently said about three- and four-receiver sets, as well as tight ends deployed more as big receivers. “Our safeties have to be comfortable executing that. Both of our safeties and a lot of our safeties, let's put it that way, have corner in the background. That's for a reason.”

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Still, though they have a lot of talent, the Eagles made it clear that it’s Cox who will be the defense’s signature player when they signed him to a six-year, $103 million extension, making him the highest-paid non-quarterback in league history. Cox played in a 4–3 in his rookie year of 2012, and he, like a lot of Philadelphia’s defenders, can be better in a scheme that plays more to their strengths. Davis seemed to struggle when trying to find that balance, but Schwartz has generally been successful when he scales back the complexities and puts the best players in position to make plays.

“There are a lot of things that are going on, on the field,” Schwartz said in May. “Our job is to try to streamline the information, allow [the players] to play fast, and give them confidence."

Most of the talk about the 2016 Eagles has been about the offense’s transition from Kelly to new coach Doug Pederson—from the hurry-up vertical to the West Coast offense. But much of this team’s success will have to rest on a defense that already seems to have the pieces in place and a new leader who understands how to find success.