The ebb and flow of generations does not concern itself with the soccer calendar. The waves do not hold back in order to accommodate a World Cup cycle. Nor do they linger a little longer because a major tournament is just a few months away.

The prime of a soccer player is a fickle thing. Some primes come early, some late. Some are brief, some long. Some don’t come at all.

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United States men’s national team head coach Bruce Arena once said that his 2006 World Cup team had peaked in 2005 – when they won the Gold Cup – but was already past it by the time the big tournament in Germany rolled around. The Americans went winless and flamed out in the group stage.

Bad timing. It happens to many national teams whose peaks and valleys don’t always align with the years that are important and those that are not. Winning a World Cup is a function not only of form and fortune, but also of the best years of the top players happening to coincide with the right summer.

Let’s circle around to the point: A young core of enormous promise is assembling within the U.S. national team in the eighth month of Arena’s second stint in charge. Of course, 18-year-old wunderkind midfielder Christian Pulisic has probably been the team’s best player for some nine months, pushing through under Arena’s predecessor Jurgen Klinsmann. Likewise, Bobby Wood, 24, had broken out at last summer’s Copa America Centenario. As did central defender John Brooks, also 24.

DeAndre Yedlin, 23, has been in the mix for a while – and has somehow raced out to 46 appearances – although it can feel at times like he’s still learning his position at right back, after being converted from a winger. Up front, the 25-year-old Gyasi Zardes has shown well in spasms. So has 26-year-old playmaker Darlington Nagbe.

Jozy Altidore, it’s easy to forget, is still only 27, even though he is the program’s third all-time leading scorer with 37 goals. He more or less dangles between the younger generation and the veteran core. Most of that older group of Clint Dempsey (34), Michael Bradley (29), Tim Howard (38), Alejandro Bedoya (30), Jermaine Jones (35) and Fabian Johnson (29) is likely headed for its final World Cup, assuming the Americans qualify for Russia.

Yet Sunday’s hard-fought 1-1 tie with Mexico at the feared Estadio Azteca seemed to announce the arrival of at least one other player – and maybe two.

The 21-year-old FC Dallas star Kellyn Acosta was fielded beside Bradley in a tandem shielding the unexpected five-man defense. And while it’s hard to distinguish yourself as a holding midfielder in a game when your team has just a quarter of the possession, he did exactly that.

In just his eighth national team game, Acosta was largely authoritative – except for the rare midfield turnover – that he seemed to immediately become a rival for Jones, who has partnered with Bradley for more than half a decade. Acosta, while not permitted to do so against Mexico, also has something to offer going forward and has shown flashes of the potential to become an outstanding passer. As such, he can shuttle between the boxes and free up Bradley to sit deep and distribute from there, where he’s at his best.

Further up the field, Paul Arriola, the tiny 22-year-old Xolos winger, was lumbered with a fairly thankless assignment in his fifth USA game. As a forward in a front three for a team designed to absorb pressure on the day, Arriola essentially had the job of running after the opposing defenders as they pinged the ball around. Nevertheless, he gave a composed performance, just as he’s previously impressed in flashes with the team having scored in his first two caps, including in a World Cup qualifier.

When the 40-man preliminary Gold Cup roster was released last month, there was a pleasant surprise in there for attentive U.S. national team fans. Mexican-American FC Dallas goalkeeper Jesse Gonzalez was listed, suggesting that the 22-year-old might be picking the Stars and Stripes over the country of his ancestry, following earlier reports to the contrary.

It’s premature to speculate over what sort of national team career he might have. That is, if he’s even one of the three goalkeepers from the six on the preliminary roster selected for the tournament, and if he makes an appearance to cap-tie him to the USA in perpetuity.

The succession issue has hung heavily over the program for a few years now, with Howard slowly aging out and Brad Guzan – who is 32 and, as a goalie, has time on his side – once again looking like a most average goalkeeper in Mexico on Sunday. The heir apparent to Howard is a mantle never quite seized by Bill Hamid, Sean Johnson or David Bingham. But between Gonzalez and Ethan Horvath, the issue might finally be solved.

But where does all this leave the national team right now? Or in a year, when the World Cup is here again? Is this a team with a nice blend of young and old? Or is it a band of veterans that are either over the hill or descending its summit, with a few not-quite-ready younger players mixed in?

That will be determined entirely by results in Russia – again, assuming the U.S. is going to Russia, which seems fairly safe now. A stray goal here or there will cast a verdict on the 2018 incarnation of the national team – as it must on all teams at the World Cup end game – to decide whether it was a year past its best, or a little ahead of its time, or just the right combination after all.

And if this isn’t the U.S. team to break through to another quarterfinal or further, perhaps the next one will be. The talent seems to be there. The trick is to get the timing right.

Leander Schaerlaeckens is a Yahoo Sports soccer columnist. Follow him on Twitter @LeanderAlphabet.

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