No single event has shaped the NFL quite like free agency. 

It happens every year, so our generation doesn't really grasp the incredible weight of it all. Yet not so long ago, the idea of players switching teams was so foreign that even when it was allowed, it never really happened. 

We live in a world where it is rare for a Ray Lewis or a Tom Brady to play an entire career with one franchise. We live in a world where it makes total sense for a Peyton Manning or a Steven Jackson to chase one last ring or one last payday away from their adopted hometown. Heck, in this world, it's fortuitous for teams to get rid of their star players when they become financially cumbersome. 

We've come so far, it's almost impossible to make out the starting gate. 

Free agency began in the NFL in 1947. Before that, clubs were able to use the "reserve rule," which was made more famous by baseball and the men who crushed it: Curt Flood and Marvin Miller.

The clause in a player's contract allowed the team to re-sign him every year to the same contract, meaning that he wasn't going anywhere unless they traded him or he decided to retire. This was considered acceptable by just about everyone until players started to step forward and demand some sort of role in these transactions. 

The first free agent to actually switch teams was R.C. Owens in 1962. When Owens left the San Francisco 49ers to go play for the Baltimore Colts, 49ers owner Vic Morabito refused to speak to Colts owner Carroll Rosenbloom ever again. 

Moreover, the very next year, NFL commissioner Pete Rozelle instituted the "Rozelle Rule." It allowed the commissioner, at his discretion, to compensate any team losing a free agent with money or draft picks—taken from the other team! If that seems like it's just a trade under the guise of free agency, that's because it is! 

Think about today's system under those rules.

Excited about your favorite team grabbing Mike Wallace? Sure! Lots of fans are. Would any of them sacrifice a first-round pick (or more) for him? Almost certainly not. Under that system, Wallace would find a slim market and have zero leverage to do anything except head back to his original team with his tail between his legs. 

After the Rozelle Rule was challenged and struck down (1976 in Mackey v. NFL), the NFL attempted what became known as "Plan B" free agency. This allowed owners to protect 37 of their players—often the best players and most potentially lucrative free agents—with the right of first refusal. This also imposed a compensation schedule to the players that was similar to the Rozelle Rule, only with rules.

This, as many might have guessed, was the grandfather of what we know as the "franchise tag" and "restricted free agency" today. 

Unrestricted free agency didn't begin as we know it until 1992. Numerous players, including four-time Pro Bowler Frank Minnifield, sued the NFL and were awarded damages due to the restrictive nature of the NFL's "Plan B."

"This is a total and huge victory," said Jim Quinn, the players' lead counsel. "For the rest of the players, liability has been found; the only issue is how much damages they get. Maybe some will get zero, and maybe some will get nearly a million like Dave Richards got.

"We are not trying to blow up the world or look for the destruction of professional sports."

[...]

Each of the eight players testified before the jury, but no owner did. Quinn said in his closing argument that although several owners -- including the Kansas City Chiefs' Lamar Hunt, the Giants' co-owner Wellington Mara and the Cleveland Browns' Art Modell -- were present for closing arguments that "not one -- and what is it, a 40-foot walk up to that stand? -- got up there because they knew they couldn't possibly defend the system."

Free agency led to more competitive balance in the league.

The dynasties of old started to crumble during the '90s, and the NFL draft took center stage as a make-or-break moment in each team's future. NFL coaches were tasked with recruiting players just like their peers at the college level. 

As can be reasonably assumed, the NFL has figured out that free agency doesn't have to be a big negative. The league considers it an event that can be optimized to create buzz and revenue.

Sure, we live in a world where buying a jersey of one's favorite player becomes a risk/reward scenario at the cash register. Fans are sad to see a player leave as easily as he was once added. 

Yet we also live in a world where 10 million people tune into the NFL Scouting Combine on their TVs and mobile devices (via NFL press release). We live in a world where the NFL draft surpasses playoff games in other sports when it once was an afterthought on the schedule for any but the most hardcore of NFL fans.  

With parity at an all-time high and an NFL year in place that keeps interest piqued throughout the offseason, it's no wonder that the NFL is making money hand over fist and is able to leverage gigantic TV contracts.

Free agency certainly changed the NFL forever, but it's also a major factor in where the league is today: America's favorite and most lucrative pastime. 

Michael Schottey is the NFL national lead writer for Bleacher Report and a member of the Pro Football Writers of America. Find more of his stuff at The Go Route.

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