A hard-fought defeat in the MLS Cup Eastern Conference Semifinal represented the end of the line for the New York Red Bulls as the squad exited on away goals in a contentious home-and-home series with Supporters Shield winners Toronto FC. For 18-year-old midfielder Tyler Adams, it was a disappointing end to a season that saw him rise into a starring role for New York.

But it also opened a door. Adams would report to his first U.S. Men's National Team camp on Monday.

"I was able to flip a new page and know that there would be a new chapter: coming into my first National Team camp," Adams said. "It's been a childhood dream of mine, and one that I'm always working towards. Wearing the crest is the ultimate goal for any player."

When the USA came up short in Trinidad last month, it ended the team's hopes for the 2018 FIFA World Cup. But it also expedited the introduction of the next generation of the Men's National Team. At a camp with three first-time call-ups and 12 players under 24, the future starts now. A new wave of players is ready to take the first steps of their National Team journey, starting with Tuesday's friendly against Portugal (3:45 p.m. ET; FS1, Univision, UniMás).

One of its harbingers arrived on a short flight from Germany for his first MNT camp appearance. Last Saturday, Weston McKinnie impressed in his first full 90 minutes with Schalke 04, a 1-0 shutout of Freiburg. The Royal Blues enter the international break sitting fourth in the Bundesliga, only six points from the top of the table. As McKennie has established himself as a regular contributor, the 19-year-old has drawn the full attention of the MNT.

After a history-making 2017, Josh Sargent's respite from the U-17 World Cup was interrupted with a call to action. Outside St. Louis, the 17-year-old was at home playing "Call of Duty" when he picked up the phone with an invitation to fly to camp in Portugal. The opportunity was impossible to pass up.

"I never thought I'd be here so soon," Sargent said. "The fact that I am is amazing. I'm just looking forward to proving that I deserve to be here. We can do it a lot sooner than we thought. It gives the U.S. hope to see a lot of young talents."

It's still surreal for the three teenagers progressing through their first MNT camp. Adams recalls watching forward Juan Agudelo score screamers for the MNT on TV. As one of the Red Bulls academy's first MLS Homegrown products, his performance was something to aspire to. Agudelo has been a professional soccer player from the time that Adams was 11-years-old. Now, the two are sitting across from each other at team meals and connecting passes through midfield.

McKennie's ties to the MNT go even further back. Growing up in a military family, the central midfielder spent three years growing up on Ramstein Air Force Base near Kaiserslautern, Germany. When the MNT visited in March 2006 for a friendly ahead of that year's World Cup, he was in the stands, watching Clint Dempsey salute the crowd after scoring on a diving header in the side's 1-0 win against Poland. Earlier in the week, he met MNT legends Landon Donovan and Carlos Bocanegra while team was quartered on the base.

"It was something that stuck with me," McKennie said. "When I got called to my first Youth National Team camp, I thought back to that moment. Who would have ever thought that I met Landon Donovan and Carlos Bocanegra at that age? I was just starting soccer - no one could say how good I was going to become. I'm going through the same stuff that they went through. It's mind blowing."

While McKennie embarked on his professional career in Germany, the trio of camp newcomers were all developed stateside in the U.S. Soccer Development Academy. After 10 years of establishing world-class environments to develop world-class players, the Academy is bearing fruit for the senior team. From a young age, the three new call-ups advanced through the ranks at their local clubs, preparing them for professional play domestically and abroad.

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Adams joined the Red Bulls' pre-academy Regional Development School at age 10. From there, he climbed through their development ranks, becoming the first player to progress through the entire program and earn a professional contract.

"It starts with the Development Academy," Adams said. "The Academy has gotten stronger and stronger over the years. The opportunities are great. Whether it's myself getting called into camp, or looking at some of the younger groups like the U-17 World Cup team and teams from other recent World Cups, they're doing great."

Sargent started with St. Louis Scott Gallagher Missouri at a similarly young age, and McKennie joined FC Dallas, one of the top Academy clubs in the country, at age 11 after his family returned stateside. Dallas led the league in MLS Homegrown player production this season, and fellow local Academy products Kellyn Acosta and Jesse Gonzalez are also in camp this week with the MNT. The Academy facilitated McKennie's success at the next level.

"I have a lot to thank FC Dallas for. They're one of the best in the country," McKennie said. "They really know what they're doing. When I made the jump over to Europe, I wasn't surprised by many of the changes because FC Dallas was a step ahead. It was easier for me."

Despite the offer of a MLS Homegrown contract after a long, successful run with Dallas, McKennie decided to test the international waters and signed with Schalke in August 2016. Sargent is taking a similar path, as he's set to sign a deal with Werder Bremen when he turns 18 in February.

After witnessing MNT star Christian Pulisic's rapid rise at Borussia Dortmund, players are looking overseas for the opportunity to raise their game. McKennie has been able to test himself against some of the world's best in Germany, and the beginning of his Bundesliga blossoming precipitated an invite to the MNT.

"I had always wanted to go back to Germany to play where I learned the sport," McKennie said. "Seeing the success of Christian over there, it was like 'I want that, I need that.' I was hungry for it, to see what places my abilities would take me. I didn't want to not know what I was capable of."

Adams' Red Bull role models are on the training field with him at this camp. Agudelo signed with the club as one of the league's first-ever Homegrowns, and Matt Miazga rose through the Academy and signed a MLS contract before a high-profile transfer to Chelsea. He's currently on loan, plying his trade as a defensive anchor for Vitesse in the Dutch Eredivisie.

"You see guys like Matt and Juan go through the Academy and they're role models for me," Adams said. "This year in the MLS, you really saw a lot of young Homegrowns make a difference within their teams. They're getting opportunities and they're able to develop. Guys in Europe are getting opportunities. All over the globe now, we have players that are doing great from a young age. The more opportunities that they get, the more that they're able to push for the National Team."

While the three have risen together through the Development Academy and Youth National Team squads, this month's camp provides them with possibly their biggest opportunity yet: representing their country at the highest level.

"You don't really know what it means until you first put that jersey on," Adams said. "You hear the anthem and you get goosebumps. You continue to get goosebumps throughout, every time I hear the national anthem."

The next generation of U.S. Soccer has the chance to start proving itself on Tuesday against the European champions. The three new call-ups seeking their first cap are as hungry as they come and understand the magnitude of the opportunity.

"I don't just think about myself when I put on the crest," McKennie said. "You represent the country. You're the voice of the country in this sport around the world. I think about the team and the fans. It's a nation that never gives up, never stops fighting. Whenever I put on the crest, it's all or nothing for me.

"If I do get to play, I'll give it all I got and make sure they call me back."