Millennials.

It isn’t a particularly frightening word, but in some ways it’s an intimidating one. At least it is to the movers and shakers in tennis. The generational concept has made them very nervous lately.

The noun applies to an enormous, very loosely defined group of people who were born in the 1980 and 90s. Identifying their habits and tapping into their resources has become the grail for consumer marketers. However, millennials are an amorphous, unpredictable bunch, as elusive as a Snapchat message. They were weaned on social media, they consume their entertainment on an array of platforms and their attention span is thought to be limited.

Millennials pose a special problem for a sport that embraces tradition as much as tennis does. The game’s leaders are worried that those celebrated four- and five-hour matches between titans like Rafael Nadal, Roger Federer and Novak Djokovic will not captivate this younger audience. There’s a growing sense that change may be in the offing, as well as a steady, rising chorus calling for reform in key areas, including the scoring system.

We are like witnesses standing in a very dark tunnel, seeing a tiny speck of yellow light at the far end. Change is coming. That little speck is the headlight of a locomotive. It can, and will, demolish anything in its path. And it is bearing down on us.

“We’re in the best place we’ve ever been,” Chris Kermode, the executive director of the ATP, told me recently. “That makes it difficult to argue for change, but we have to anticipate what pitfalls we see in the next 10, 15 years. What about our next generation of fans? We have to ask millennials what appeals to them, what it will take to get them to watch and attend tennis.”

The lords of tennis don’t believe that millennials hunger for more matches like the nearly five-hour 2008 Wimbledon final, in which Nadal beat Federer, 6-4, 6-4, 6-7 (5), 6-7 (8), 9-7. (The marathon is hailed by many as the greatest match ever played.) That’s the conventional wisdom about millennials and their appetites, anyway.

As a result, the ATP is undertaking a comprehensive review of its operation as we approach the 2018 expiration of the 10-year “Brave New World” agreement that has brought unprecedented prosperity and stability to the ATP tour. In the search for newer and braver, Kermode said, all options are on the table. The ATP will look at its calendar and tour structure, as well as proposed innovations including an on-court shot clock and alternative scoring systems.

The first glimpse of this braver and newer world will be seen as early as next year, when the ATP introduces a parallel World Tour Finals for the top eight under-21 players. Kermode said the ATP also will incorporate innovations suggested by fans, which could be a twist as drastic as no-ad scoring, or using the 10-point super tiebreak in place of a third set. For a number of reasons, starting with age restriction, this tournament will not offer rankings points. What’s interesting is that this puts the ATP in the business of promoting exhibitions.

Is this a harbinger?

The headlight of that locomotive has just grown a little larger. . .

The players, according to ATP sources, want to see improvements and involvement from tournaments, and they also want the ATP to accommodate new investors. They don’t want to see the current formula set in stone. The problem is that the format created almost 10 years ago (the three-tier approach of 250, 500 and Masters 1000 tournaments) has been extraordinarily successful.

According to Kermode, the nine elite Masters 1000 events at the top of the tour pyramid have produced a 73 percent growth in the television audience (to over 510 million) since the format was adopted in 2009. And while some critics have complained that the grind has become too demanding, the players are earning more, and they’re enjoying longer careers.

“Those (Masters) tournaments can get bigger,” Kermode said, alluding to rumors that the ATP might create a category of “Super Masters” within its present framework.

A tournament like Indian Wells certainly has the potential to be a de facto Grand Slam, at least in terms of its sheer bigness, prize money, popularity and media profile.

An even more robust Masters 1000 program would help justify any decision to experiment with innovations at the ATP 250 level. Kermode sees distinct possibilities there, and believes the tour must ask itself three questions: Is the length of matches right? Does the typical match need more dramatic moments? Does it need more big points?

Or, you can put it this way: Should the tour seriously consider no-ad scoring (first to win four points takes the game; first to five or seven points takes the sudden-death tiebreaker), or even Fast4 (four-game sets, employing no-ad scoring, and the five-point sudden-death tiebreaker at 4-all)? Even a hard-fought five-set match using Fast4 scoring can be over in 90 minutes—a fact that makes television producers salivate.

Players, as a rule, are a conservative group. Back in the 1960s, they mounted bitter resistance to the introduction of the tiebreaker. Many still talk as if eliminating the let serve would destroy the soul of the game. On the other hand, the tiebreaker, Hawk-Eye, no-ad scoring and super tiebreaks all have become familiar features on the tennis landscape, right up to the Grand Slam level. (Mixed doubles at the U.S. Open employed no-ad scoring and super tiebreaks.)

That yellow disc of light, it’s getting even larger . . .

Women’s matches are, on average, significantly shorter than men’s matches. Yet when Steve Simon, the CEO of the WTA, met with reporters at the Wuhan Open last week, he aggressively advocated for no-ad scoring and super tiebreaks.

“The attention spans of the audience today is shrinking,” Simon said, according to Sport 360. “Everybody wants it in very short nuggets.”

Kermode acknowledges that players, like most people, don’t like change. In the case of his constituency, their success also may make them wary of innovation. But he thinks that research and data may win them over.

“The important thing is to show someone the strategy behind change,” he said. “Once you demonstrate the benefit, it’s easier to make it happen.”

It’s ironic, but the pros themselves are millennials. Yet simple habit may prevent them from recognizing that the way they play and present the game may be out of lockstep with the mentality of their own peers.

Upon hearing of Simon’s comments, Nadal had these words for the AFP:

“The kind of matches that stay on in the memory, and on the history of our sport, are a bit [longer] matches and dramatic matches that become emotional,” he said. “If you want to change the values of the sport, maybe yes. [But] tennis has values that we need to follow, in my opinion."

Nadal makes an interesting point that neither Kermode nor Simon nor any television producer—nor even well-intentioned, progressive administrators—can refute. If by design all matches will last between 60 and 90 minutes, what will distinguish the great ones from the very good ones? Epics are one of the great selling points of pro tennis; will the game be better off, or even more popular, when it’s no longer possible to have them?

Only millennials know the answer to that. And they’ll let you know soon enough—as soon as that train they’re on, the one with that great big headlight, now blazing and almost here, arrives.