It's a billion-dollar industry, by any accounting. Fans love it. Websites like Bleacher Report, ESPN, NFL.com and Yahoo give it top billing. New companies offering advice on it emerge seemingly daily.
We all know that fantasy football has exploded.
But what do those in real football think of it? At first, many were dismissive. But now?
"You hear players talking about it...'I need fantasy points!'" Chicago Bears defensive end Jared Allen said. "It's connected fans to players even more. Now they feel they can truly play Monday Morning Quarterback from the couch.
"Fantasy football is a huge part of our game."
You don't get the eye rolls from players when you mention it anymore.
The players are players now.
Vikings kicker Blair Walsh says he's in a league with teammates. Veteran Cardinals backup quarterback Drew Stanton was in one with 10 Lions teammates his rookie season. Cardinals receiver Larry Fitzgerald has never played fantasy football but said he sees how much it benefits the NFL.
"It's great to see people playing and bringing fringe fans to the game," he said.
To get a real sense of the fantasy football landscape within the real football landscape, Bleacher Report recently polled 24 players, asking different questions (and different numbers of questions) depending on the players' positions and involvement. The results were candid and insightful. Much can be learned from their responses, both about how to approach fantasy football and how NFL players approach real football.
First off, of the 24, only 10 admitted they played fantasy football.
Walsh doesn't hide the fact he's a huge fan.
"It lets you be competitive, and it lets you be a general manager," Walsh said. "I think that's exactly what fans want: the power to choose players and pick scenarios and situations."
Vikings teammate Brian Robison has been approached several times about playing fantasy football, but he's always rebuffed the invitations.
"I feel like my time should be spent on concentrating on my job, instead of worrying about what else is going on around the league," Robison said.
New York Giants guard Geoff Schwartz said he's played twice during his professional career, both times when he was on injured reserve.
"When I'm healthy and playing," Schwartz said, "I don't have the time."
Of the 10 players who said they had played fantasy football, eight said they had drafted a teammate. Cincinnati Bengals receiver Mohamed Sanu has tried to draft as many of his teammates as he can.
"I couldn't get A.J. Green," Sanu said. "Why not draft the people you got confidence in? There are other great players in the league, but you got to draft your boys!"
Vikings safety Harrison Smith said half his team last year was comprised of former Notre Dame teammates.
Blair Walsh admitted he tends to be a "homer" in fantasy football because he gets to see what his teammates are doing on a daily basis. "I pick up guys who might play more and get more reps," Walsh said. "I guess that's the insider trading of fantasy football."
Stanton said he prides himself in projecting a breakout player from his own roster.
"I always try to get a sleeper at the end [of the draft] that people don't know about that I think will be good," said Stanton.
Three of 24 players couldn't muster a guess when asked what percentage of players play fantasy football. But of the 21 who did venture a projection, the range varied from 1 to 75 percent.
"Rarely do I hear anyone say they participate in it," said Panthers cornerback Teddy Williams, who was responsible for the 1 percent projection.
Vikings teammates Robison, Walsh and center John Sullivan, interviewed separately, all projected that 75 percent of players participated in fantasy football. The Vikings, though, may be the exception rather than the rule. Twelve of the 21 players who provided an estimate said fewer than a third of NFL players play fantasy football.
It's probably a team-to-team thing. Stanton said his Lions teammates did play fantasy football, but his Cardinals teammates seem not to.
Or maybe whether players admit it is a team-to-team thing. Dallas Cowboys defensive tackle Ken Bishop, who guessed that half of NFL players played fantasy football, said, "I think people play but don't talk about it."
When asked how many of the players who play fantasy football actually draft themselves, 17 responders provided a percentage. Bishop provided the low with 30 percent, while the remaining 16 guessed it was at least 50 percent, including seven that said 100 percent.
"Every last one of them if they were able to pick themselves," Sanu said. "If you don't, it would be foolish."
These are, after all, elite athletes with no shortage of confidence.
"Let's be honest," said one offensive lineman, who requested anonymity. "These are guys who play in the best league in the world and have large egos. I'd draft myself, if I could."
Jared Allen guessed that 85 percent of players who play fantasy football would pick themselves. "Everyone is confident in their own abilities," he said, "so of course they'll draft themselves."
Walsh is a kicker, Stanton and Matt Hasselbeck quarterbacks and Johnson and Sanu are receivers. Each of them has played fantasy football, and they play positions where they could select themselves in a fantasy draft.
Sanu and Johnson admitted to doing just that, while Stanton said that he has not.
In October 2009, Hasselbeck confronted a classic fantasy football dilemma: who to start at quarterback? His team was auto-drafted, and he ended up with himself and Brett Favre, who had led the Vikings to a 4-0 start. Out of sheer pride, though, Hasselbeck usually started himself. But heading into Week 5, Hasselbeck—who had missed two games for the Seattle Seahawks with broken ribs—decided to start Favre. Bad decision: Hasselbeck tossed four touchdowns against the Jacksonville Jaguars while Favre had a pedestrian one-touchdown, one-interception game.
"It was anybody's guess how I would play," said Hasselbeck, now the Colts' backup QB. "I followed my gut."
The question players were most skittish about was, "What percentage of players do you think play in leagues for money?" Which makes sense considering a spokesman for the NFL told me the league policy via email:
Fantasy football games and League or Club-sponsored skills competitions (e.g., racquetball tournaments, "Club Olympics" events) for prizes generally are not considered to be gambling or a gambling-related activity, provided that there is no wagering on the outcome. NFL Personnel may not, however, accept prizes with a value in excess of Two Hundred Fifty Dollars ($250) in any fantasy football game. This prohibition is intended to avoid any appearance of impropriety which may result from participation in fantasy football games by individuals perceived to have an unfair advantage due to their preferential access to information.
Only 13 players provided an answer, with the percentages ranging from 0 to 75 percent.
"Guys bet on everything," said Bengals linebacker Trevor Roach, who guessed 75 percent.
But Walsh, who plays annually, said he doesn't know the policies for players playing in fantasy football leagues for money.
"It's not worth the trouble," he said. "To me, it's about talking smack to my friends."
Schwartz didn't provide a percentage, but he guessed it would be very low because of the risk of players being punished for their involvement. "It would not be smart to do that, because how much money can you really win playing fantasy football? It's just not worth the risk."
So who would these players select with their top pick?
Out of the 19 votes cast, Packers quarterback Aaron Rodgers was picked by six players. Then came Vikings running back Adrian Peterson and Colts quarterback Andrew Luck with three votes apiece, followed by Seahawks running back Marshawn Lynch and Broncos quarterback Peyton Manning with two each.
"He's steady and pretty good every year," Cowboys linebacker Andrew Gachkar said of Lynch.
Seahawks quarterback Russell Wilson, Steelers running back Le'Veon Bell and the Lions defense each received a vote.
Defensive players were asked if facing a fantasy football star motivated them. Only one of the 12 said that it did.
"You do get hyped, because if you stop them then the defense is doing good," Bishop said.
But Roach said focusing on that would be a huge distraction. "If you're getting hyped up for fantasy, then you're doing it for the wrong reasons. You should try to win every game like it's your last."
Lions defensive end Corey Wootton pointed out that a fantasy football star tends to be a star in the game, too. Veteran defenders Jared Allen and Charles Tillman, though, admitted they have no clue who fantasy football stars even are.
"I have no idea how it works," Tillman said.
Only one player said he was aware of fantasy football points during a game in which he was playing.
"That's become a part of our culture," Stanton said. "That guys' fantasy football team is going to win singlehandedly, because Jamaal Charles went for 180 yards."
Cleveland Browns quarterback Josh McCown and Fitzgerald said they focus on reality football, not fantasy football, on game days. "Once you're in a game, you're in a game," McCown said. "The points I'm worried about are on a scoreboard, and that's it."
Added Fitzgerald, "Couldn't be further from my thoughts."
Five players were asked if there was a sense of pride in being owned on a fantasy football team, and they unanimously said no.
"I wouldn't say it's a sense of pride," Sanu said, "but I think it's cool that people say, 'I got you on my fantasy football team!' It doesn't make or break my day. Being in the NFL gives me a sense of pride, because it's something I worked and strived for."
McCown said that pride may mean more to younger players. "Some of these younger players were possibly playing [fantasy football] in college," McCown said.
Players had strong opinions on how fantasy football has evolved since they entered the league. Schwartz said it's changed the way fans watch the game.
"Guys get tweets because they performed well for [an owner's] fantasy team," he said. "It's kind of skewed how fans view the game. A guy could have a good week and not score a touchdown. But in the eyes of some fans, they've had a bad week. Guys get hurt, and they hear from fans about it."
Wootton said he didn't hear much about fantasy football when he played at Northwestern University.
"When I first got into the league, it was really starting to grow," he said. "Now it's a big business. It's really been booming the last few years."
Fantasy football, Sullivan said, gives fans a sense of ownership. "Granted, I think we see more backlash for players, when they don't perform, because fans feel entitled. They almost feel hurt by a player's lack of performance. But their passion is a good thing. It only drives up the interest in the sport and therefore the dollars and the cents."
The fan interest in fantasy sports has created an interesting sense of "ownership" between fans and players. In some circumstances, the stakes for fans playing in fantasy leagues are very high, which trickles into how fans will interact with athletes.
McCown recalled a time back in 2013 when he was the starting quarterback for the Bears and was coming off a five-touchdown game against the Cowboys. He was approached by a man in his 40s at a north suburban Chicago mall.
"For five minutes, he ran through the whole thing, almost a play-by-play of what happened," McCown said. "I was trying to be patient with him. He was obviously very excited.
"I mean, it was cool, but that was kind of crazy."
Walsh recalled one man who said he won $1,000 because Peterson was stopped short of a touchdown, and Walsh booted the game-winning field goal against the Packers.
"I think it's cool," Walsh said. "We won the game, and it put some money in his pocket. I hope he could buy his wife something nice."
But fans also go too far sometimes.
Vikings receiver Charles Johnson watched the Bengals play the Falcons. Early in the game, star receiver A.J. Green suffered a toe injury. Johnson tracked social media to see the extent of Green's injury. He was disgusted by what he saw many fans posting.
"All I saw were fantasy players talking about how they hate him and called him racial slurs because he only scored one point instead of saying, 'Hope you get well soon and get better,'" Johnson recalled. "I was kind of upset about that. I was like, 'It's just fantasy football. This is someone's livelihood.'"
Johnson has also received some questionable posts.
"They say, 'You suck. You got to make that catch,'" Johnson said.
Once, when Johnson should have scored a touchdown but fumbled near the goal line, "Someone said, 'If you would have gotten that touchdown, I would have won!'" he recalled. "Some guys take it more serious than others. Fantasy is cool. Just don't get too out of hand with it. I'm not here to win you fantasy leagues or earn points. I'm ultimately here to win games for the Vikings."
In all, 21 players were asked if fantasy football has helped or hurt the NFL. One of them said neither, and the remaining 20 said that fantasy football helped the league.
"I think it's helped in the sense that it brings in a fan or someone who might not necessarily be a football fan or might not necessarily have a reason to watch on the weekend," McCown said. "Anything that brings more eyes to the sport. The genuine interest in fantasy football is a good thing."
Tillman said he knows a lot of women who pay more attention to the NFL because they participate in fantasy football leagues.
"I think it's helped because it's helped the NFL make more money. I can't tell you how many women I know who are into fantasy football. Church leagues, everybody on my softball team. It's everywhere." Schwartz said fantasy football makes watching games more interactive.
Hasselbeck said his 12-year-old daughter plays in a league where you pick five players each week.
"She loves it," Hasselbeck said. "She watches players from around the league. She's really into it. She knows all the bad teams."
It's clear that even though all NFL players aren't playing fantasy football, they generally do view it as favorable for their league.
For 16 years, Sean Jensen served as a beat writer or NFL columnist for the Milwaukee Journal Sentinel, the St. Paul Pioneer Press and the Chicago Sun-Times. He has also been an NFL contributor or columnist for AOL Sports, Yahoo Sports, Sporting News, Sports Illustrated and ESPN The Magazine.