TEAM of INTEREST PHILADELPHIA EAGLES

If you thought mad scientist Chip Kelly would rein in his experimentation in 2014, guess again. He's amped up R and D for his O this off-season, replacing one combustible element with a key ingredient from a rival

EAGLES FIRST-YEAR coach Chip Kelly strolled up the sideline seeking a better view of the field goal that was about to end his season. Seeing Saints kicker Shayne Graham's 32-yard attempt split the uprights as time expired, Kelly—his tongue characteristically resting on his upper left lip, a quirk of his—commenced a defeated march toward midfield.

Graham's kick only sealed the inevitable. New Orleans, trailing 24--23, had bulled 34 yards in 10 plays, all but one of them runs. The drive devoured 4:54, Philly's underrated defense wearing down just enough at the worst time. The fans filing out of Lincoln Financial Field had feared this would happen: Because of the torrid pace of Kelly's offense, the defense had been on the field for 71.9 plays per game during the regular season, the most since the expansion Browns in 1999.

The bitterness of a home playoff defeat has been known to prompt many an NFL coach into making changes, reshaping his approach to something more reflective of the league's norm. It's a better-safe-than-sorry mentality. But nearly three months after that playoff loss (and 15 months after Kelly was pried from Oregon), it's clear: Kelly is welding the Eagles into his own image, NFL mores be damned.

If there was ever any question about Kelly's confidence in his ability to manufacture a passing game through sheer design, it vanished when the Eagles re-signed receivers Riley Cooper (five years, $22.5 million) and Jeremey Maclin (one year, $5.5 million) in February, before free agency began. Last July 27, Maclin tore his right ACL; four days later, video emerged of Cooper's drunken racial outburst at a Kenny Chesney concert. Few would have blamed the club for not pressing its luck and letting the recovering Maclin and the markedly average Cooper hit the open market this spring. But Kelly now knows that his system can work with Cooper in it. And while Maclin might still be a mystery, his east-west fluidity and commanding stop-start quickness seem tailored for the scheme.

Not that the scheme is prisoner to players with these traits. DeSean Jackson has them in spades, but the Eagles released him last Friday. Rarely is an electrifying 27-year-old receiver coming off a 1,332-yard season deemed replaceable. But this may be the deepest receiver draft class in history, and the Eagles most likely believe they can find a replacement (sidebar), avoiding Jackson's $10.5 million cap hit and locker room drama.

It's also entirely possible that Jackson's replacement was, in fact, tabbed weeks ago when they sent a fifth-round pick to the Saints for Darren Sproles. A soon-to-be-31-year-old backup running back does not typically replace a young Pro Bowl receiver. But the 5'6" Sproles is not a typical back, and this is not a typical offense.

PERHAPS THE biggest misconception in pro football is that Kelly's offense is revolutionary. (Biggest Supporting Misconception: that opponents will "figure out" Kelly's offense after a year of studying it.) In actuality the Eagles don't run many plays that the NFL hasn't seen before, and they tilt more toward the basic than the complex. Their repository of mostly zone-based tactics features heavy doses of misdirection and either/or options that create conflicts of assignment for defenders. Principles of the system include myriad screens, multilevel crossing patterns, seam routes married to deep outside dig and post routes, and zone runs seasoned with read-option elements. A typical NFL offense, so far.

But a typical NFL offense also dabbles in secondary staples. The Eagles, generally, do not. Kelly's playbook is thinner, not thicker, than most. With fewer plays to practice, Philly can master them well enough to execute at breakneck pace from a host of exotic formations. These include: horizontal stretches, with wide receivers aligned closer to the sideline than to the field numbers; multireceiver overloads, often with three wideouts distributed evenly across one side or with two tight ends on the line and no wideouts to their side; elongated presnap motions, with players sweeping full-speed across the formation; and unbalanced lines, usually with a tackle and a tight end swapping spots.

Defenses have seen most of these wrinkles before—but not snap after snap and at a furious no-huddle pace. The rapidity creates the illusion of volume and complexity and, in the heat of battle, rattles a defender's psyche the same way that actual volume and complexity do.

In essence, opponents become reactionary and predictable. Defenders don't have enough time to communicate disguises, coverage rotations or blitz exchanges when the ball is snapped quickly. And they're not as comfortable unleashing exotic ploys against formations that they don't often see. Plus, with the Eagles using the entire 53.3-yard width of the field, defenders often find themselves isolated in space.

That ability to render defenses predictable was a big reason quarterback Nick Foles, a third-round pick in 2012, threw for 27 TDs (versus two INTs) and a league-best 119.2 passer rating last year. Foles is not endowed with upper-echelon tools. His arm strength is good, not great. His accuracy appears stellar, but that's partly because he has not yet cultivated the pocket awareness and anticipation skills to regularly attempt throws into tight windows—a prerequisite for top-level QBs.

But Foles is smart enough, and his shortcomings are rarely a problem given that Kelly's system calls for plenty of defined throws (best example: screens) and either/or progression reads that leverage synchronized route runners against a lone defender (examples: multilevel crossing patterns and seam-and-backside-dig combos).

Foles's success was also a testament to Kelly's knack for adjusting. At Oregon, Kelly's hallmark read-option and moving-pocket designs hinged on QB mobility. Foles is more athletic than his gangly 6'6", 243-pound frame suggests, but he's no Michael Vick. And while Kelly still called read-options for Foles here and there, making defenders account for the threat, his beloved staple became an afterthought midway through 2013.

This wasn't Kelly's only adjustment. A popular sentiment in NFL coaching circles is that after 23 years in the college ranks, Kelly was surprised by how much man coverage his Eagles faced early on. He shouldn't have been. Man-to-man is the soundest way to defend a fast, multiset offense. Instead of trying to quickly diagnose one formation after another, defenders can count off: I got him, you got him. Moreover, everyone had watched Andy Reid's Chiefs stifle the Eagles' receivers with press-man coverage in Week 3. Opponents figured that if Reid—who as Philadelphia's previous coach was familiar with those receivers—chose to play them with press-man, then press-man must be the way to go.

Indeed, it was. Kelly saw what Reid already knew: The skeletal Jackson, unexplosive Cooper and sturdy tight end Brent Celek all struggle to shed jams at the line. That's problematic in a system predicated on synchronized route timing and spacing. So Kelly added more man-beater concepts, ratcheting up presnap motions and crossing patterns to give his receivers the advantage of operating more on the move. Ultimately the receivers' deficiencies against press coverage cost the Eagles in their postseason loss to the Saints. But if not for Kelly's adjustments before that, the Eagles most likely wouldn't have been in the postseason to begin with.

Whether the Eagles can advance in the playoffs this season will be largely determined by how well Sproles fills Jackson's role. Jackson's damage was set up primarily by bubble screens, swing passes, wheel routes and shallow crosses—which is precisely how the shifty Sproles made his living in New Orleans. In three years with the Saints, Sproles caught 232 passes for 1,981 yards, both highs among running backs.

It's true, Sproles is not a vertical threat in the mold of Jackson, which might make him seem an ill fit in a passing game that last season led the NFL with 80 plays of 20 yards or more. But consider: In Kelly's system, deep throws are often set up by horizontal decoy routes—an area in which Sproles offers tremendous value. And a lot of the long passes come off of catch-and-runs. According to Pro Football Focus, only 28 of Philly's 80 long pass plays came from wide receivers catching balls that traveled at least 20 yards through the air. The Eagles averaged a league-best 7.0 yards after the catch. Sproles can keep much of Philly's vertical game intact while Cooper and, especially, Maclin reap the benefits.

And then there's Sproles's contribution to the ground game. It's easy to forget that Philly's zone-based rushing attack was the league's most productive (160.4 yards per game; 5.1 yards per carry). Sproles presents a versatile complement to the NFL's reigning rushing leader, LeSean McCoy. A staggering 81.1% of McCoy's yards from scrimmage last season came with at least three wide receivers on the field, as the widened formations and presnap motions often dragged defenders out of the box, creating commodious zone-running lanes for the most laterally explosive back since Barry Sanders.

Sproles will undoubtedly spell McCoy, who endures a great deal of reps in Kelly's nonstop system. More important, Sproles will also line up alongside McCoy, adding another viable rushing threat to a backfield that was lethal with just one. Expect even more misdirection concepts in 2014, especially given the athleticism of the O-line, which features fast-improving right tackle Lane Johnson along with Philly's other two offensive re-signings: Pro Bowl left tackle Jason Peters and ascending fourth-year center Jason Kelce.

IN MAY the Eagles will hold their first minicamp of 2014. Kelly will ceaselessly blare music to simulate crowd noise; he'll conduct multifaceted drills in which all players, regardless of rank, take reps simultaneously; and he'll implement the sideline signals for his hurry-up offense. The tempo will slow only during intermittent "teach" periods, where players and coaches have a chance to converse. The practices will last just under two hours each.

During the regular season the Eagles will practice in similar fashion for three days midweek, including Tuesdays, which the rest of the league mostly treats as an off day. They'll have a gentle walk-through on Fridays and then a short but fast-paced practice on Saturdays. It's a weightier workload than players are accustomed to—one that many initially disfavored. But attitudes softened as it became increasingly apparent: There's not just a method to Chip Kelly's madness, but a method that might really work.

An aging backup running back does not typically replace a young Pro Bowl receiver like Jackson. But Sproles is not a typical back, and this is not a typical offense.

DeSean Gone, Moving on

The Eagles should feel confident that they can draft a replacement for receiver DeSean Jackson, who was released last Friday. Chip Kelly could give his offense another dimension by bringing in a bigger target; or, given how smoothly his system functioned in 2013, he might want one with attributes similar to those of the 5'10", 175-pound Jackson. Philly will have plenty of Jackson-like options with the 22nd pick on May 8, or even later in the draft.

Paul Richardson

Colorado 6 feet, 175

PROJECTED: 2nd or 3rd round Skinny downfield burner. Scouts love his ball-plucking ability.

Odell Beckham

LSU 5'11", 198

PROJECTED: 1st round Excellent route runner. Explosive after the catch. Likely more effective inside than Jackson.

Brandin Cooks

Oregon State 5'10", 189

PROJECTED: 1st round Biletnikoff winner has tremendous burst on screens. Tough to corral, especially from the slot.

Bruce Ellington

South Carolina 5'9", 197

PROJECTED: 3rd or 4th round Former SC point guard has innate understanding of field spacing, vital in Kelly's scheme.

Tevin Reese

Baylor 5'10", 163

PROJECTED: 5th round A true burner who can separate from man coverage. Used mostly as a speed artist. Might need to expand routes.

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Photograph by DREW HALLOWELL/PHILADELPHIA EAGLES/GETTY IMAGES

BACKFIELD AND MCCOY No back last season came within 260 yards of McCoy, whose 1,607 yards made him Philly's first rushing champ in 64 years.

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GREGORY SHAMUS/GETTY IMAGES

WORTH THE GAMBLE By re-upping the controversial Cooper (14), the Eagles are betting not on the receiver but on Kelly's system, in which Cooper has thrived.

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JED JACOBSOHN FOR SPORTS ILLUSTRATED (DESEAN JACKSON)

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DOUG PENSINGER/GETTY IMAGES (RICHARDSON)

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DERICK E. HINGLE/USA TODAY SPORTS (BECKHAM)

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SCOTT OLMOS/USA TODAY SPORTS (COOKS)

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RICHARD SHIRO/AP (ELLINGTON)

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PETER G. AIKEN/GETTY IMAGES (REESE)