By Dan Durkin-

(CBS) Five seasons ago, the New York Jets pushed reset, using the nouveau rebuilding approach of bringing in a rookie head coach (Rex Ryan) and quarterback (Mark Sanchez) tandem. The initial results of this plan were rich, as the Jets reached back-to-back AFC Championship games and appeared primed for sustained success.

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At the time Ryan was hired, he was a 12-year NFL assistant with a proven track record as a defensive savant. Since taking over the Jets, his defenses have never ranked outside the top 11. They’ve thrived at creating pre-snap conflict with multiple looks, hybrid coverages and a bevy of pressure packages.

However, as dynamic as the Jets are on defense, their offense was stagnant. They could only mask the deficiencies on offense for so long.  Teams began to load the box to force Sanchez to beat them, and he simply couldn’t. The wheels fell off late in the 2011 season and carried over to 2012, forcing the Jets to reassess their quarterback situation.

In 2013, they invested an early pick on Geno Smith, and a quarterback competition ensued. Sanchez was winning the competition yet was inexplicably playing in the fourth quarter of the third preseason game against the Giants when he suffered a shoulder injury that resulted in season-ending surgery. Smith won the job by default, and Sanchez is now in Philadelphia.

The 2014 Jets look very similar to every team Ryan has been in charge of, one that plays suffocating defense with a run-first approach on offense.

Offensively, the Jets operate a balanced attack primarily out of three-receiver personnel groupings. They like to get foes into nickel, spread them out and attack inside with zone runs, zone read, gadget plays and quarterback draws.

The Jets have a stable of running backs with complementary styles and skill sets. Chris Ivory is an aggressive, downhill runner who runs behind his pads as he attacks the line of scrimmage. Chris Johnson, while nowhere near as explosive as he once was, is the speed threat to the perimeter.

The idea is to keep their legs fresh while protecting their second-year quarterback as he develops and learns to read defenses and better understand route combinations.

Smith is raw in his ability to recognize coverages and complete his progressions. This got him into frequent trouble as a rookie, as he stared down primary reads and threw contested routes. In all, Smith turned the ball over 26 times, six of which were returned for touchdowns.

The challenge for offensive coordinator Marty Mornhinweg will be to get Smith to understand how his footwork and depth of his drops are tied to the routes being called. Smith honed his craft under at West Virginia under Dana Holgorsen, who runs a modified version of Hal Mumme’s air-raid offense, which is a scheme predicated on sight adjustments and reads at the line of scrimmage that allow the quarterback to make pre-snap decisions on where he’s immediately going with the football.

Smith must now learn how to process more information post-snap and see how a defense unfolds before he pulls the trigger.

For years, the Jets have lacked playmakers in the passing game. This past offseason, they threw $15 million guaranteed at wide receiver Eric Decker. In Denver, Decker benefited from the tremendous receiving talent surrounding him and a Hall of Fame quarterback in Peyton Manning throwing him the ball. How Decker performs in a primary receiver role remains to be seen.

Draft-bust Stephen Hill (drafted two slots ahead of Alshon Jeffery) was cut, leaving Jeremy Kerley as the No. 2 receiver. Kerley is a shifty open-field runner and will operate primarily out of the slot.

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For young quarterbacks who may be gun shy about working the ball to the sidelines, having an effective tight end to patrol the middle of the field can be a security blanket. This past May, the Jets selected Texas Tech’s Jace Amaro, an ultra-athletic tight end who could develop into a matchup challenge. Amaro’s learning curve will be steep as an in-line blocker, because he was primarily lined up off the line in college.

At one point, the Jets offensive line was a strength of the team, but their play has slipped of late. Center Nick Mangold remains one of the best in the league at his position, but the rest of the line is inconsistent in getting movement on defensive fronts.

Defensively, the backbone of the Jets’ 3-4 hybrid scheme is formed by their dominant defensive line.

First-round picks Muhammad Wilkerson and Sheldon Richardson form one of the league’s best defensive end pairings.

Wilkerson may be the most productive-yet-unheralded player in the league. He’s a long, angular athlete who is brutally strong at the point of attack. Richardson was thought to be an ideal three-technique in a 4-3 scheme, yet Ryan has transformed him into a two-gapping force on the edge. By occupying two blockers with ease, these two keep linebackers clean and create singles for the nose.

As is the case with most 3-4 defenses, it’s only as good as the person manning the center shade. Undrafted Damon Harrison has exceeded every possible expectation. By using a low get-off, active hands and quick feet, Harrison’s surpassed Kendrick Ellis and has evolved into a force on the interior.

There are a few pieces missing on Ryan’s scheme though, and one is an edge rusher. Quinton Coples, a former first-round pick, hasn’t lived up to his draft status. Coples mans the weak side but is stiff and robotic in his movements. On the strong side, veteran Calvin Pace is steady, particularly against the run. But neither generates the pressure needed to make this scheme really take off.

The other key piece that is missing from Ryan’s scheme is a shutdown corner. While trading cornerback Darrelle Revis in 2013 was a wise move from a football operations standpoint, on the field, the Jets are scuffling to find his replacement.

With Revis, Ryan ran hybrid coverages, in which Revis locked down half of the field on his own. This allowed Ryan to use zone-blitz pressure packages from various angles that disguised where the pressure was coming from. This creates uncertainty for protection schemes, typically tilting the math in the defense’s favor.

Dee Milliner, a 2013 first-round draft pick, was drafted to be Revis’ replacement, but he has struggled since entering the league. As Milliner works his way back from an ankle injury, the Jets are left with Antonio Allen and Darrin Walls.

This past May, general manager John Idzik bypassed on an opportunity to select a cornerback like Darqueze Dennard or Jason Verrett and instead opted for Louisville safety Calvin Pryor.

Safeties play a big role in Ryan’s defense, both as run support players and blitzers, so the playmaking Pryor is a natural fit. However, if Milliner doesn’t take a big step this season, Idzik will face a lot of scrutiny for not making a more concerted effort to improve the talent level at cornerback.

The Jets defense will keep them in games, but will an offense that lacks playmakers in the passing game and features a developing quarterback provide enough firepower to win games? It’s a down year in the AFC East, so certainly the pressure is on the Jets (1-1) to break through from their recent run of mediocrity.

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Dan Durkin covers the Bears for CBSChicago.com and is a frequent contributor to 670 The Score. Follow him on Twitter at @djdurkin.