The job of a national team coach is no longer to just be a coach.
Part of the role now - like at club level - involves recruitment, with the coach a representative of their international program in this ever-evolving world of dual-nationals.
U.S. Soccer understands that fact better than most, having been involved in a number of recruitment battles over the years.
Several, meanwhile, are still ongoing, including the one for Valencia starlet Yunus Musah, who is highly-coveted by both the U.S. and England after shining as part of a European-based U.S. men's national team in November.
And, ahead of their upcoming friendly with El Salvador with what is essentially an entirely new squad, several new battles have come to light.
The 18-year-old midfielder is one of the more highly-touted youngsters in MLS and, having previously made the leap from the U.S. to El Tri, appeared to be one that got away before reopening his the fight for his international future with this call-up.
But Alvarez is not the only dual-national that has come into focus with the USMNT's latest squad announcement. In fact, of the 23 total players called in by Gregg Berhalter, eight have the option to play for someone other than the U.S.
"It's common in today's day and age, to have players that have multiple passports," Berhalter told reporters. "It's not an uncommon thing, and it's something that we deal with.
"What I'd say is they're still young players and they still have the world in front of them. All we want to do is bring them into our environment and show them what our environment is about. Then it's going to be up to them to make a decision in the end where they end up committing to.
"We'll be fine with that whatever decision they make, but I think it's important that players are able to see what we do and how we work."
Berhalter's squad, which features a total of 11 uncapped newcomers, is littered with players that may eventually face those decisions.
Defenders Julian Araujo and Marco Farfan join Alvarez and goalkeeper David Ochoa in being eligible for Mexico.
Toronto FC's Ayo Akinola, who scored nine goals in just 15 MLS appearances this season, could also be that answer, though he remains a target for Canada.
Frankie Amaya is also eligible for Mexico, though he was forced to pull out of the squad after testing positive for the coronavirus.
The two most intriguing players, however, are Alvarez and Orlando City's Andreas Perea considering their current situations.
Now, though, his call-up hints that he is at least somewhat open to committing to the U.S. long-term.
Like Alvarez, Perea has represented another country at youth level, having started all five matches for Colombia at the 2019 U20 World Cup.
The 20-year-old, who was born in Florida, had his own breakthrough this season on loan with Orlando City, having previously come through the academy of Colombian powerhouses Atletico Nacional.
As a result of their youth experiences, both Alvarez and Perea would need to file a one-time switch to play for the USMNT going forward.
With regards to Alvarez, Berhalter says that the LA Galaxy star - who Zlatan Ibrahimovic once referred to as his "cub" - has not started the process of changing sides. Doing so would leave him permanently tied to the USMNT, unable to return to the Mexico set-up.
Berhalter, though, did leave open the possibility that Alvarez could be available by the time the U.S. kicks off against El Salvador on December 9, but he is under no pressure to do so.
"I guess you could take it one or two ways right? You can say he played for us and then he played for Mexico and we're gonna hold that against him and we're never going to call him again and we'll let that be that, but that's not the way we look at it," Berhalter said.
"We're talking about extremely young players, about players with cultural ties to other countries where emotion is involved. I can understand a player making a decision like that one time in his career.
"For us, again all it is about is saying there is an open door and we want to create an environment that players want to be in. We want to attract good quality players, and then the rest is up to the player to decide."
By the time the U.S. camp ends, those decisions may not be made. The dual-nationals not named Alvarez or Perea will still have their options open, with the upcoming friendly not being enough to cap-tie them to the USMNT.
Alvarez and Perea, meanwhile, could certainly postpone their own decisions by using this camp simply as a test-run, one which would not see them commit either way.
And Berhalter would not blame them for doing so. The recruitment phase has begun, but as these situations continue for players all over the world, Berhalter understands that they remain complicated.
"The way I'm looking at it, in times like this, I think it's smart of a player to see what's out there and to see what's available," he said. "We're talking about really young players, and both of them have a history with the United States, but they have cultural ties to other countries.
"So, to me, this isn't an unusual process and, again, all we're looking to do is to create a good environment for players that they want to play."