The Seahawks right now are as trendy as the city they hail from. Just about every offseason NFL power poll ranked them No. 1. Fantasy owners laud their young stars. Vegas has them among the favorites to win Super Bowl XLVIII.

Coach Pete Carroll and general manager John Schneider, who partner in making personnel decisions, seem to share everyone’s high expectations. Schneider has a gift for seeing the benefits of a player’s strengths. Carroll and his staff have a gift for accentuating those strengths. Together they’ve built an offense around a third-round pick who has all the physical and mental skills but was supposedly too small to play quarterback. And they’ve built a defense around a fifth-round pick and an undrafted ex-Canadian Leaguer who were uncommonly strong but supposedly too big and stiff to play cornerback.

Now, four years into the Carroll/Schneider plan and fresh off an impressive divisional round playoff appearance, this young, deep and talented team’s window of opportunity is widening. Schneider and Carroll spent the offseason making emphatic over-the-final-hump moves. Taking advantage of a soft free-agent market, they signed defensive ends Cliff Avril and Michael Bennett and nickelback Antoine Winfield at bargain prices. Tacitly acknowledging the weakness of this year’s draft class, they shipped their first-round pick to Minnesota for wide receiver Percy Harvin. Though Harvin will begin the season on the PUP list, recovering from hip surgery, this is still a huge trade, at least theoretically. Harvin has the potential to revolutionize not just this offense, but offense in general. We’ll get to how and why shortly, but let’s first examine the defense that has the whole league talking.

DEFENSE

Richard Sherman far right (Elaine Thompson/AP)

The common belief is that cornerbacks Richard Sherman and Brandon Browner are what make Seattle’s defense work. The common belief is correct. Throughout his career Pete Carroll has run some variation of a zone-based 4-3. Here, he runs a 4-3 man-zone hybrid. His original defensive coordinator in Seattle, Gus Bradley, believed in taking away the offense’s lanes along the boundaries. Bradley’s thinking was that by eliminating the outside and narrowing the field, you give the offense less space to operate and the defenders less to worry about. This makes for a more predictable offense and a more aggressive defense.

More Seahawks

TROTTER: A Team Full of Coaches

SHERMAN: Where I'm Coming From

KING: One-on-one with Golden Tate

KING: Seahawks Postcard

KING: Russell Wilson Back in Flight

BEDARD: The NFL's Knowledge Gap

Bradley earned the head coaching job in Jacksonville this offseason, but new coordinator Dan Quinn, who had been the defensive line coach, will continue the same general approach. With Sherman and Browner stifling the outsides, Quinn has the extremely rare luxury of scheming to defend a narrowed field with nine players. Having the league’s fastest safety, Earl Thomas, patrolling the middle will allow Quinn to call single high coverage nearly every snap. That means hard-hitting strong safety Kam Chancellor can be a true rover, giving this defense unique freedom for aggression and disguise.

Under Bradley, the Seahawks almost always ran a basic combination of 4-3 under and over fronts with a single-high look on the back end. But five or six times a game, usually in critical third-and-long situations, they would get very creative with amoeba sub-package looks and blitzes. Quinn wants to expand on these and perhaps even integrate some of their concepts into the base 4-3 and nickel. New slot corner Antoine Winfield will figure prominently in this.

The Winfield acquisition solved a lot of problems. Great as Sherman and Browner are, neither is comfortable playing inside. More and more, offenses were compelling one of them to play inside by aligning both receivers to the same side in base personnel sets (this is called a “slot formation”). Winfield is a slot defending maestro and one of the best tackling corners of all-time. With him around, the Seahawks now have the option of defending these sets with their nickel packages. This will be an easy way for Quinn to increase the frequency of Seattle’s more creative looks.

Quinn might be forced to play more nickel anyway, as offenses now realize that the best way to attack this field-narrowing D is to spread out and look for mismatches away from Sherman and Browner. This is why, unless oft-injured Walter Thurmond can somehow regain his 2010 rookie form, it’s vital that 36-year-old Winfield stay healthy (he has missed at least six games due to injury every other year since 2007). And it’s important that last year’s good-looking sixth-round pick, Jeremy Lane, continue to develop. The Seahawks may also have to count on young reserve safety Jeron Johnson, who brought good speed to the dime blitz packages last year, a tad more in coverage.

The Sherman-Browner factor is not the only inspiration offenses have for spreading out against Seattle. Many offenses struggle to run against this stingy front seven—especially when there’s a safety always available to drop in the box. The Seahawks last season faced the second fewest rushing attempts in the league.

Red Bryant (Charles Rex Arbogast/AP)

It starts with a stout front four. Defensive end Red Bryant is 6-4 and 320-something pounds of immovable girth. In most schemes he’d be a tackle, but Seattle likes to use him as a two-gap anchor on the strongside edge. If Bryant struggles with injury and performance like he did last season, the Seahawks will likely try newcomer Michael Bennett in his spot. Bennett weighs only 274 pounds, but in a similar scheme with the Bucs he consistently used his lateral quickness to make plays in traffic from the outside. If the mild shoulder problems that have recently bothered Bennett worsen, 2012 seventh-rounder Greg Scruggs will get more action.

Inside, underrated nose-shade tackle Brandon Mebane has a relentless motor and a natural sense for leverage. He’s a respectable penetrator and extremely disruptive east-west run-clogger. At the three-technique, departed free agent Alan Branch’s size and surprising suddenness were huge assets against the run. The Seahawks believe former Dolphin Tony McDaniel or last year’s fourth-rounder, Jaye Howard, can fill Branch’s shoes. To hedge these bets, they used a third-round pick on Jordan Hill and a fifth-rounder on Jesse Williams, who played multiple positions along Alabama’s three-man line. Williams somehow fell to the fifth round even though some esteemed talent evaluators said they saw little difference between him and mid-first-round pick Star Lotulelei.

At the weak defensive end spot will be Cliff Avril, though he could ultimately share some of his first and second down snaps with Chris Clemons if the incumbent veteran bounces back from his January ACL injury. Either way, the Seahawks will have a speedy, sinewy athlete here. Also taking some snaps in this spot on passing downs will be 2012 first-rounder Bruce Irvin (after he serves his four-game PED suspension). Critics originally said it was imprudent to spend the 15th overall pick on a situational player like Irvin. But in today’s NFL everything is situational. Last season Irvin played 48% of the snaps, many of which were third downs or other critical moments. Able to stay fresh, he recorded eight sacks and wrecked numerous other plays with his explosive speed-rush and unexpectedly forceful bull-rush. This offseason Irvin has gotten reps at outside linebacker, where he figures to headline most of Quinn’s expanded hybrid concepts. So far, he is more than delivering fair value for Pick 15.

It seems almost unfair that sandwiched between the league’s best secondary and one of its best front lines is a very smart, athletic young linebacking corps. Mike backer Bobby Wagner got better each week as a second-round rookie last season. He is sharp in keying and diagnosing against the run, but more importantly, he’s athletic and able to identify shallow route concepts as a zone defender. Flanking Wagner on the strong side is K.J. Wright, who can cover most tight ends. On the weak side, replacing veteran Leroy Hill will be Malcolm Smith, who did a solid job attacking in traffic when he filled in as a starter last season. If Smith struggles with a full-time load, the Seahawks can turn to longtime special teamer Heath Farwell or recently added ex-Cardinal O’Brien Schofield.

OFFENSE

Pete Carroll and Percy Harvin (Elaine Thompson/AP)

A revolution is coming. Percy Harvin’s unexpected hip surgery has put it on hold for presumably at least the first half of the season. But still, it’s coming. Schneider and Carroll would not give up a first-round pick and $25.5 million in guaranteed money for a player with Harvin’s history of health and attitude problems if they didn’t believe they were getting something extraordinary in return. Some might characterize Harvin, who was leading the league with 62 receptions when he went down with an ankle injury midway through last season, as the true No. 1 receiver that Seattle’s offense was missing. But that’s not what he’s here to be.

A true No. 1 receiver runs downfield routes and commands double-teams over the top. Harvin will operate predominantly within 10 yards of the line of scrimmage. And he’ll do his greatest damage at or behind the line of scrimmage. More and more, the focus of NFL offense is on getting the ball to weapons in space. Harvin, with his tremendous acceleration and surprising strength when quickly changing directions, is the ultimate weapon in space.

Seahawks offensive coordinator Darrell Bevell has already laid the perfect schematic foundation for integrating Harvin. At the beginning of last season, Bevell was not quite sure what he had in Russell Wilson. So, early on, he kept his schemes simple and measured, using a lot of two-back and two-tight end sets. This kept defenses in vanilla base looks for Wilson. Whatever downfield shots the quarterback took were off defined reads and controlled, designed pocket movement. In fact, the Seahawks used play-action on an extraordinary 35% of their snaps. That was the second most in the league and second most since Football Outsiders started charting the stat in 2005. (The Redskins last year used it 42% of the time.)

Russell Wilson (Ted S. Warren/AP)

Wilson improved exponentially over the course of his rookie season. He showed great touch on elevated seam passes and deep balls. He almost never forced tight throws. Unable to see over his linemen, he moved around a lot in the pocket but rarely got frenetic. Though mobile and accurate throwing on the move, he resisted the temptation to rely on his legs, running only when his reads demanded it. As a runner, he never subjected himself to big hits.

As Wilson progressed, so did the sophistication of Bevell’s game plans. The Seahawks eventually went to more three-receiver sets and used finer-crafted route combinations. But having a tenacious, highly skilled traditional running back like Marshawn Lynch, along with a decent fullback in Michael Robinson, Bevell could see that his team was at its best when working off the ground game. He came up with a marvelous way to lean on the run and still take advantage of his rapidly improving quarterback’s skills: read-option looks. Wilson had threatening mobility, and Seattle already had a zone-blocking front line. The Seahawks started doing more read-option concepts around late November, and it gave defenses fits.

This is where the revolution begins. Harvin will be a significant weapon on wide receiver screens, reverses and probably even some backfield carries and swing passes. But what makes him a truly worthy investment is the new wrinkle he can bring to Seattle’s read-option. Defenses already have enough trouble identifying and staying disciplined in their assignments against static read-options. Imagine if that equation were to include pre-snap motion from a dynamic force like Harvin. Or what about post-snap motion? Imagine Wilson faking to Lynch, rolling out and still having an option to pitch back or fling the ball forward to Harvin. Or, imagine Lynch getting the ball but Harvin screaming behind him from the other direction for a possible reverse. There are myriad possibilities for paralyzing defenders. This is the next phase of football’s evolution. It’s not just the read-option, but the broader concept of multiple challenges to defenses: lining up multiple players who are multidimensional and capable of simultaneously going in multiple directions.

Marshawn Lynch (Todd Kirkland/Icon SMI)

This would be a radical new approach to offense, but the Seahawks aren’t at the mercy of it working—which is why they’re equipped to survive Harvin’s absence just fine. They have enough resources outside of Harvin to still function, maybe even thrive, in a more traditional approach. Lynch is the best tone-setting ballcarrier in football after Adrian Peterson. Supporting him is 2012 fourth-rounder Robert Turbin, who has shown some upside as a thicker-bodied third-down back. There’s also second-round rookie Christine Michael, a compact, straight-line thumper who was brought in partly because it was apparent late last season that Lynch needs a slightly lighter load.

In the passing game, Seattle lacks elite straight-line speed, though the Seahawks were very successful going downfield last season thanks to Wilson’s touch and Bevell’s ability to get players open by design. Sidney Rice is the beneficiary of most scheme-created mismatches. Golden Tate has leveraged his shifty quickness into a respectable catch-and-run role, while Doug Baldwin generally capitalizes on his opportunities out of the slot. Needing to add more size on the outside, the Seahawks also drafted 234-pound Chris Harper in the fourth round.

In the fifth-round, Schneider and Carroll thought they were buttressing their tight end depth when they selected Luke Wilson. But a season-ending Achilles injury to Anthony McCoy (arguably the club’s most improved player in 2012) means Wilson now may assume the No. 2 tight end duties behind the fundamentally sound and moderately flexible (though not particularly dynamic) Zach Miller. Also in the mix is undrafted second-year pro Sean McGrath.

Tasked with maintaining smooth sailing for these skill players is a front five that’s extremely athletic in the two most important positions, and just good enough at the other three spots. First, the athletes. There aren’t many left tackles as physically gifted as Russell Okung. Last season the 2011 sixth overall pick stayed truly healthy for the first time in his career and earned a trip to the Pro Bowl. Okung has great natural power as both a run- and pass-blocker. The other athlete is center Max Unger. His mobility is critical to the collective movement of Seattle’s zone blocks, though it’s his improved strength that allows his crafty angles to stalemate nose tackles.

Filling the guards spots are James Carpenter and Paul McQuistan, though J.R. Sweezy and John Moffitt could both challenge for playing time. Carpenter and Moffitt are the most physically gifted, but they’ve also been the most susceptible to injuries. At right tackle is Breno Giacomini (pronounced Jah-coe-mee-nee, which is fun to say once you get the hang of it). He is a classic play-to-the-whistle fighter. The only concern is his susceptibility to penalties and bull-rushes.

SPECIAL TEAMS

Kicker Steven Hauschka was 23/23 on field-goal attempts under 50 yards last season and 1/4 from 50-plus. Punter Jon Ryan had just three touchbacks on 65 punts and left 30 of those punts inside the 20 (fourth best rate in the league). In the return game, Percy Harvin is too electrifying on kickoffs to not use once he gets back. He took at least one kick to the house in each of his four seasons with the Vikings. On punt returns, Golden Tate would make sense.

BOTTOM LINE

The Super Bowl hype makes sense, but getting there won’t be easy. This team is still young at quarterback and will be counting on players to step up in the modernized passing game. There could be some growing pains.

Andy Benoit is diving deep into each team’s prospects for 2013. Read what he’s done so far.