Are pro athletes playing too much Fortnite? Some teams are worried.

Attendees play in the Epic Games Inc. Fortnite: Battle Royale Celebrity Pro Am on the sideline of the E3 Electronic Entertainment Expo in Los Angeles on June 12, 2018. Fortnite has attracted 45 million players worldwide and is generating hundreds of millions of dollars a month in sales. Bloomberg/June 12, 2018

The men across the table were worried. Riley Sutter knew that now. It was early June and Sutter was in Buffalo, New York, for the NHL scouting combine. At first, the question surprised him. Maybe it was joke? But as the Washington Capitals' eventual third-round draft pick shuttled from room to room, from interview to interview, teams repeated an inquiry that seemed to intrigue and unnerve them.

Are you addicted to Fortnite?

Fortnite is the wildly popular multiplayer online video game where up to 100 players drop onto an ever-shrinking island and battle to be the last one alive. Last fall, the game became a global pop-cultural icon with tens of millions of players and more than $1.2 billion in revenue. The game is free, available on computers, gaming consoles and phones, and a fixture in locker rooms across the sports world.

One Capitals prospect called Fortnite "the fad of the generation right now," his third priority after, in some order, school and hockey.

Sutter later learned those teams asked all the players the same thing because, two weeks earlier, a reporter claimed an NHL insider had told him a recent high NHL draft pick would never make the pros because he was "addicted" to Fortnite. It ignited fear in front offices leaguewide.

The more Sutter thought about it, the more it made sense. Sometimes after getting off the ice, he liked to stand in his recovery boots and play for an hour before bed, and he knew other players struggled with self-control issues.

"There's definitely some guys around the league, some even on my [junior] team, that are pretty bad for it," Sutter said. "It takes away from their sleeping and keeps them up late ... It's starting to become a pretty big issue."

As the popularity of Fortnite and other video games has grown among people of all ages and backgrounds, the sports world reflects this new reality. After French soccer player Antoine Griezmann scored in the World Cup final, he celebrated with the game's popular "Take the L" dance. A few days later, MLB players acted out their favorite Fortnite celebrations for an ESPN segment during the All-Star Game. Yet video games' imprint on the sports world does not end with just one title.

Before the Stanley Cup Finals, the Capitals and the Vegas Golden Knights -- even those who wouldn't call themselves gamers -- played hours of Mario Kart to fill their copious downtime and relax while on the road. From English Premier League stars to more than half the Los Angeles Lakers team to Washington Redskins rookie running back Derrius Guice, athletes across the globe play video games for hours on end, streaming on platforms such as Twitch or YouTube for hours to have fun, promote causes and connect with people. (Twitch is owned by Amazon, whose CEO, Jeff Bezos, also owns The Washington Post.)

Gaming's popularity has increased along with the frequency of questions about whether or not it is a detriment. Early this season, Boston Red Sox pitcher David Price swore that a missed start because of carpal tunnel syndrome was not the result of regularly playing Fortnite with teammates. When Guice fell from a projected spot in the first round of April's NFL draft despite being regarded as one of the best running backs available, many believed concerns over his video-game habits worried the league about his maturity.

One agent who represents NBA players noted he heard concerns this past season of fatigued players from team personnel.

"It's not something the teams will come to you about. A coach or GM won't say [anything] but trainers do," the agent said. "Teams with really young players complained all year about guys not sleeping. It used to be chalked up to them partying and all that, but now it's because of them playing video games all night."

"I haven't really talked much with guys about it," one NBA executive said. "I'm not really concerned, but I probably should be since I'm sure they're staying up late as hell playing."

The sporting world's questions about the impact of long video gaming sessions coincide with growing attention toward the potential dangers of whether lengthy stretches of gaming constitutes problematic behavior, or something more than a habit. In June, the World Health Organization recognized "gaming disorder" as a mental health condition for the first time, defining it as compulsive playing that negatively impacted other parts of life.

Medical experts cautioned against overreaction to the WHO decision, stating that playing for hours doesn't equal an addiction, while the video-game establishment rebuked the WHO's reasoning as "deeply flawed." Video-game addiction has been called "the Wild West," because there is no central authority to quality-control treatment options or answer questions.

"Mainstream culture is in some ways trying to understand video games better, in ways that are sometimes critical and other times straight-up alarmist," said Nathan Grayson, a video-game writer for Kotaku, a video game website "But we should look at how we interact with these things, because they are one of the most pervasive mediums on Earth now. They're worthy of scrutiny on that basis."

Sports organizations remain concerned because long hours spent gaming exact a cost from athletes who often need to maintain strict training regimens and practices in order to achieve successful careers -- and help the teams that pay their salaries.

The fear of the Capitals is that games such as Fortnite could erode a foundational practice of their developmental system: eight to 10 hours of sleep per night. Before last season, the Capitals instructed Olie Kolzig, the former Capitals goalie who is now a coach with their minor league affiliate in Hershey, Pennsylvania, to monitor players' cellphone usage. The organization knew some junior-hockey players had "a problem" because looking at screens less than an hour before bed affected their sleep. This coming season, management trusts Kolzig's players will know the same rule applies to Fortnite.

Yet, Kolzig finds himself in the same predicament any parent faces because video games are integral to his players' culture. So, he'll ask they discipline themselves to an hour a day, or something close, and to not play before bed.

"It's a big issue and it could affect performance," Kolzig said. "But they're grown men ... You can't hold their hand and force-feed them [advice]. They have to make those choices."

Riding herd on young players is nothing new for sports teams' developmental personnel, but the source of the concern is unfamiliar to the older generation now given that task. Seemingly none of the Capitals front-office members knew about the Fortnite fretting until head amateur scout Steve Bowman, who had read an article about it, broached the subject at the NHL's combine. There, the Capitals team, including assistant general manager Ross Mahoney, asked prospects how to play Fortnite, what was the objective and how it got so big.

"I had no idea of this game and the culture that surrounds it," Mahoney said. "I'd never heard of it. I just ..." He paused, thought and reached a conclusion: "Wrong generation, apparently."

Lucas Johansen, a first-round pick by the Capitals in 2016, called the questioning "a little absurd" when he heard about it and compared it to teams asking prospects if they liked playing sports.

"It doesn't matter," he said. "As long as they show up to work ready, right?"

It can be difficult for those in gaming culture to explain how it works to those on the outside, because the culture lives on platforms based upon never-ending streams of content. The speed can create a generational gap in homes and locker rooms nationwide. In late June at Capitals development camp, players and executives played roles in a scene older than all of them.

There is Steve Richmond, the director of player development who had never heard of Fortnite until his colleagues started buzzing about it: "We used to be worried about drinking, but now it's video games. What kind of fun is that? God."

There is Johansen, the prospect who laughed at the idea that any of his colleagues hadn't played: "It's a downtime thing, I wouldn't be concerned. If you've played, then you know."

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The Washington Post's Isabelle Khurshudyan and Tim Bontemps contributed to this report.