Denis Poroy/Associated Press

If the first three days of free agency told us anything, it’s that the wide receiver position is considered more valuable than ever. Six of our top 10 free-agent receivers are already signed, while several others have been picked up or given new contracts. Traditional thinking has long been that a good offense needs a playmaking star at No. 1 receiver, a reliable possession target at No. 2 and a darting third-down maestro in the slot at No. 3. But look closer at the transactions this week and you’ll see that these roles are becoming less relevant.

It’s still ideal to have a No. 1 playmaking receiver. Hence, Calvin Johnson’s monstrous new contract, the Bucs’ signing of Vincent Jackson ($26 million guaranteed) and the Bears’ trade of Brandon Marshall (a pair of third-rounders given up). But when you examine these deals from both directions, you see the full scope of today’s evolving N.F.L. And that scope reveals that the true No. 1 receiver class is incredibly small – too small to include Marshall and Jackson.

The Bears acquired Marshall because they felt they needed an aerial playmaker once and for all. But why did the Dolphins give him up (and for below market value, no less)? Marshall’s off-field problems were seemingly the final straw, but they most likely wouldn’t have been if not for new head coach Joe Philbin’s system. In Green Bay, Philbin’s system did not center on a No. 1-2-3 receiver pecking order; it centered on creating mismatches out of various formations.

Most of those formations involved three wide receivers and an athletically gifted tight end (Jermichael Finley). Whichever player drew the most favorable matchup became the No. 1 receiver. That’s why Green Bay’s best receiver, Greg Jennings, averaged 73.0 yards per game while Jordy Nelson – a No. 3 receiver in the “old days” – averaged 78.9 yards per game. Jennings was targeted 7.7 times per game, Nelson was targeted 6 times per game and Finley 5.8. There isn’t a “No. 1 receiver” in that group – there are simply three very good targets.

Philbin’s democratic passing offense puts a premium on catch-and-run quick strikes. That’s not a perfect setup for the more methodical Marshall. Thus, when Philbin was hired, the troubled No. 1 receiver suddenly became just a troubled receiver, making him very tradable in the eyes of the Dolphins.

A similar line of thinking showed up in the Vincent Jackson move. The Bucs got a good player and a much-needed jolt to their passing offense, but more revealing is that the Chargers were content to replace Jackson with Robert Meachem. The Chargers know that Jackson is a better player than Meachem (even if Norv Turner is trying to convince the masses that the 27-year-old ex-Saint is a “No. 1”). But in San Diego’s system, Jackson is not $12 million-better than Meachem ($12 million being the difference in total guaranteed money the two players got). Turner’s offense is predicated on generating big plays through five-and seven-step drop passes. As someone who has averaged 16.1 yards per catch in his career, Meachem fits in. That’s all he needs to do – the Chargers know that their system is good enough that their wide receivers simply have to fit in. (This was verified in 2010 when the Chargers, without Jackson for 11 games, without Malcom Floyd for five games and without Antonio Gates for six games, still managed to rank first in total yardage and second in scoring).

Occasionally, the system and the player go hand in hand. With Sean Payton’s system, the Saints need a big-bodied seam-runner in the slot. Thus, they re-signed Marques Colston. Because he fills a niche (and plays with a similar-styled talent in Jimmy Graham), Colston is more valuable as a Saint than he’d be on any other team. The same logic applies to Wes Welker and the Patriots. Both are more valuable to each other than anyone or anywhere else.

The common thread among all these “system teams” is a top quarterback. Miami doesn’t have one, but Philbin’s system derived from Aaron Rodgers’s work in Green Bay. In San Diego, Meachem will catch balls from Philip Rivers. Colston catches balls from Drew Brees; Welker from Tom Brady. This is what the experts are really talking about when they say that the N.F.L. is now a quarterback-driven league. It’s not just about having a star quarterback who can make great plays – it’s about having a star quarterback whom you can build your entire scheme around. When you truly have one of those quarterbacks, your evaluation of wide receivers changes.

These quarterback-driven “system teams” also feature predominantly three-and-four-receiver offenses. As it so happens, they do this out of what’s technically base personnel (two receivers, one tight end). But when the tight ends are guys like Jimmy Graham, Jermichael Finley, Aaron Hernandez, Rob Gronkowski and Antonio Gates, the effect is the same as three-wide receiver personnel: an offense revolving around creating alignment-based mismatches with three viable targets. The Steelers are another example. They don’t have an elite receiving tight end, but they have an elite quarterback and three very, very good young receivers in Antonio Brown, Mike Wallace and Emmanuel Sanders.

When you don’t have a star quarterback, you’re stuck in the past, evaluating wideouts in the No. 1-2-3 mold. Teams in this spot are really rolling the dice when investing in receivers. Take the Jaguars and Laurent Robinson. Giving a breakout star like Robinson $14 million guaranteed was probably wise given that a paucity of receiving talent completely neutered the Jaguar offense last season. But there is absolutely no evidence suggesting that Robinson is dynamic enough to create mismatches simply by being on the field. Same goes for Pierre Garcon, who got $20.5 million guaranteed from the Redskins – a team apparently so desperate for receiver help that they’re willing to pay guys nearly double what they’re actually worth. Garcon is an up-and-coming player, but he’s also a product of the Peyton Manning system.

The Jaguars and the Redskins, both of whose offenses are built around traditional two-wideout packages, are banking on their new receivers being good enough to build a passing system around. But we see it no longer works like that. As the elite teams have shown, the N.F.L. is now about creating mismatches with three-and four-receiver formations. If you want to build a truly successful offense around the outdated No. 1-2-3 formula, your No. 1 receiver needs to be insanely talented. As the film shows and the market verifies, only three receivers currently fit this bill: Andre Johnson, who became football’s highest-paid receiver in 2010; Larry Fitzgerald, who became football’s highest-paid receiver in 2011; and Calvin Johnson, who became football’s highest-paid receiver earlier this week.

Johnson is the exception to this off-season’s rule. The Lions have a three-receiver offense, but schematically and logistically, it’s an offense built around Megatron. That’s fine. When a player is as gifted as Calvin Johnson, you build around him. What good teams understand (and bad teams don’t) is that Calvin Johnson can play the role of Calvin Johnson, but a merely productive Pro Bowler can’t – even if you give him big bucks. The Calvin Johnsons come around only once every three or four years. Systems are nourished and replenished every year.

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