ALLEN PARK, Mich. -- Glover Quin didn’t feel comfortable enough, not even after four years in Houston. Not even after signing a five-year, $23.5 million free-agent contract with the Lions before the 2013 season.

He had established himself in the NFL. But he had not done enough yet, in his opinion, to participate in one of the league's newer traditions.

Not until last season, when the Pro Bowl safety led the league in interceptions, did Quin feel his reputation was strong enough to jersey-swap.

“I never felt that people wanted my jersey,” Quin said. “So man, I want to ask him for his jersey but he probably don’t want my jersey so I won’t do it. So my first four or five years in the league, I didn’t really swap with anybody because I felt that people wouldn’t really want my jersey.

“They still may not want my jersey, but at least I feel a little bit more comfortable because I played with some of them guys at the Pro Bowl or met them at the Pro Bowl or maybe they’ve seen me on [NFL Network's] 'Top 100' or something like that.”

It isn’t clear when the first NFL jersey swap happened -- with as many as 16 games per weekend, it would be tough to trace -- but it has increased dramatically in popularity. Rarely does a week or game go by where a postgame jersey swap doesn’t occur and show up on social media, often in pictures from players or teams.

There is a code to jersey swapping. Players focus on the position they play (Quin is trading only with safeties for now), college teammates or offseason training partners.

Sometimes they’ll trade with the guy they match up with.

“I love to trade with receivers,” Arizona cornerback Patrick Peterson said. “You’re only going to play this game for so long, and the more memories you have, they last a lifetime. So to have an opportunity to collect a guy’s jersey and put it up in my trophy room in my house where I can see it forever, it’ll help me reminisce -- ‘Oh, I remember when I made that play on such and such,’ or ‘I remember where that grass stain came from.’

“I think it helps us as co-workers. I think it helps us grow closer to each other, and it just shows the respect that we have for one another when we want to trade off jerseys.”

It’s a respect thing, either for the player at your position or the opponent you’ve faced. Sometimes, when one player is at the start of his career and another is toward the end of his, it becomes a culmination of childhood idolizing turned reality.

Earlier this month, Lions cornerback Darius Slay shot a message over Twitter to Arizona’s Tyrann Mathieu. Slay is a habitual jersey swapper -- $200 per replacement is paid to the Lions, he said, a cost that varies by team -- and he wanted to try to secure Mathieu’s jersey before the game even started.

It isn’t always strategized, although both Slay and Quin go through the schedule separately before the season to plot jersey swaps. Often, swap-planning happens Sundays either through a conversation during warm-ups or spontaneously after the game concludes.

Lions wide receiver Calvin Johnson, right, swaps jerseys with Seahawks cornerback Richard Sherman after the Seahawks' Monday night win in Week 4. AP Photo/Elaine Thompson

“[I] just talk to them before the game,” said Lions receiver Calvin Johnson, whose jersey is one of the more coveted in the league. “Let them know that I want it, and then we do it after the game.”

Johnson has swapped with Peterson and Denver receiver Demaryius Thomas, who replaced him at Georgia Tech. He does it because he wants to claim jerseys of players he respects and ones he played against.

Johnson doesn’t know his jersey count, but he eventually wants to hang the ones he has in his home -- a common theme among players.

Quin has his framed and stacked up in Texas, but hasn’t hung them yet because he’s building a new home in Houston. He’s still plotting to trade with Kansas City’s Eric Berry and Oakland’s Charles Woodson later in the season -- one a contemporary; the other someone he watched growing up.

“Twenty years from now, when I’m not in the league, I still have memories of this guy as a player and this guy,” Quin said. “People come to my house and say, ‘Hey, you got this nice jersey right there.’ Yeah, I remember this guy and this guy.”

The origins of the jersey swap come from rowing and -- more famously -- soccer. According to FIFA’s website, the practice started after a France-England match in 1931, became more popular in the 1954 World Cup and gained notoriety after Pelé and Bobby Moore, the English captain, swapped jerseys after a Brazil-England World Cup group-stage match in 1970.

It is a World Cup, too, that might have started the uptick in American football jersey swaps.

Lions cornerback Rashean Mathis, who said he would swap jerseys with only Peyton Manning, said that when he started in the league in Jacksonville in 2003, the practice wasn’t done. The postgame sign of respect was a handshake and maybe a quick conversation.

Then the United States men’s national team caught the nation’s attention during the 2010 World Cup, with Landon Donovan’s dramatic goal against Algeria to push the United States into the knockout stage.

Seeing international athletes make the exchange might have triggered what you’re seeing in the NFL now.

“It could have,” Mathis said. “It was big in the U.S. [Soccer] grew large in the U.S. that year.”

In any given week, splashes of other colors can protrude from the Honolulu blue and silver typically in Lions lockers. Recently, Quin had Earl Thomas' Seahawks jersey hanging off the side of his locker. A locker over, Slay had one from college teammate K.J. Wright in his.

Players often start off by trading with their longtime friends. It was how Golden Tate started -- like Johnson and Quin, he wanted to use them at his house as man-cave decorations.

Like Quin, he was hesitant to do it his first couple of years in the league. It took Tate's “becoming relevant” for his collection to build. He also started thinking about his future and how he’s facing elite athletes weekly.

Now, it’s blossomed.

“I have a pretty nice collection,” said Tate, who entered the NFL in 2010. “I got Damian Williams. I got two of [Jermaine] Kearse's now, both Seahawks obviously. I got Marshawn [Lynch]. I got Sherm [Richard Sherman]. I got Breno Giacomini. I got one of my brother’s, [Wesley, a former Vanderbilt running back]. Jimmy [Clausen's, his college quarterback at Notre Dame].

“Jimmy’s is framed in my man cave right now. One of mine, I have a bunch of mine, obviously.”

It’s a collection that’ll grow, too.

And as a player’s relevance rises, he realizes there might be times when he wants to execute trades with multiple players at once. That causes some issues.

Giants receiver Odell Beckham Jr. ran into that against San Francisco in October. He arranged a swap with safety Eric Reid, and then Colin Kaepernick wanted to make an exchange as well after the game. So he’s going to ship an extra to San Francisco to make sure both can have the Beckham Jr. for their own collections.

NFL players, perhaps more than anything else, understand their careers are finite and can end instantaneously. So swapping jerseys is a way for them to remember their past in the future.

“It’s just something I like doing,” Beckham said. “And something I’ll be able to look back on years from now as a great memory.”

Reporting from NFL Nation Cardinals reporter Josh Weinfuss and NFL Nation Giants reporter Dan Graziano were used in this report.