Stop me if you’ve heard this one: the NFL is a passing league.

That last sentence isn’t breaking news. Fans have known for years that the league has slanted in favor of the passing game. How else do you explain Joe Flacco tossing for 3,610 yards in 2011 — a plateau that Hall of Famer Troy Aikman never reached in his career?

Now teams are learning that flying could be more expensive than driving. Early in the 2012 NFL free agent signing period, wide receivers have been moving faster than green beer on St. Patrick’s day … and for high prices.

Eight years, $132 million (with $60 million guaranteed) for Calvin Johnson? Okay. Five years, $55.55 million for Vincent Jackson? That’s understandable. But five years and $42.5 million for Pierre Garcon? Two years, $12 million for Josh Morgan?

What in the name of Alvin Harper is going on here? Receivers have gotten bigger, stronger and faster and the rules governing them have changed, but individual production from the position hasn’t taken major steps forward. Megatron’s impressive 2011 season (90 rec., 1,681 yards, 16 TD) is arguably on par with Randy Moss’ 2007 campaign (98 rec., 1,493 yards, 23 TD).

But it’s a brave new NFL world we live in and general managers appear to still be learning the landscape. When three different quarterbacks throw for 5,000 yards in the same season after it had only previously been done twice in the history of the league, it’s mandatorily going to change the way front offices build their teams. Yet, until there’s a nearly foolproof plan to get the ball in the hands of your best receivers, big contracts for wideouts will always be a gamble. And the results of that gamble could determine whether this receiver bonanza continues in the future.

Since not everyone can be lucky enough to grab a Calvin Johnson, building a solid receiving corps could be a pricey proposition. Gone are the days when teams could throw money at a workhorse running back. Now that money has to be spread out. Take the Saints for example; they were able to keep Marques Colston (and at five years, $40 million, it looks like a bargain), but did it at the expense of Robert Meachem, who took $25.9 million over four years to head to San Diego. The Redskins just committed $54.5 million to a pair of generally unproven receivers and they still have yet to negotiate anything with their presumed first-round draft pick, Robert Griffin III.

Oh, and eventually you’ll need to find that key tackle who can keep your franchise signal-caller upright.

So far, the Detroit Lions seem to have found a way to make this work within the system — and when’s the last time we could say something like that? After signing Johnson, they convinced Matthew Stafford, Nate Burleson and Ndamukong Suh to restructure their contracts. Now if only every team could find such talented and selfless teammates.

Meanwhile, Mario Manningham continues to run the NFL streets looking for a No. 1 receiver-type contract. Big dreams for a man who has never caught more than 60 passes in a season. But in this environment, he very well could get it. Whether he lives up to such a deal could determine if any of his contemporaries ever see anything like it again.