Jonathan Gonzalez will not be involved for Mexico at the Under-20 World Cup in Poland next month but Real Betis' Diego Lainez has been included in the squad.
Dual-national Gonzalez switched over from the United States in early 2018 and was involved for El Tri's full national team last year, but was moved to the U20 squad in 2019 and was expected to play a leading role for Mexico in Poland.
However, as ESPN reported last week, Liga MX side Monterrey have blocked the 20-year-old from participating in the tournament.
"The Jonathan case has been mentioned a lot, it's too much that my phone rings for two or three weeks exclusively for one player," said U20 head coach Diego Ramirez in a news conference on Tuesday in Mexico City. "I believe the Mexican national team is made up of 21 [players] and not just by one player.
"I can say that [Gonzalez] is a great person and a great player," he continued. "It seems that the policies of his club [Monterrey] didn't permit him to participate with us."
Mexico head coach Gerardo Martino had announced that Lainez would be included with the U20 squad and is set to miss out on the Gold Cup, having been part of the Argentine's first senior squad in March. The 18-year-old is the only foreign-based player on the 21-player list.
Leon's Juan Jose Macias is the highest Mexico-born goal-scorer in Liga MX this season with seven goals, while Pachuca's Roberto de la Rosa has excelled at U20 level.
Mexico kicks off its U20 World Cup campaign against Italy on May 23 and will also face Japan and Ecuador in Group B of the tournament.
LA Galaxy dual national striker Efrain Alvarez was included in Mexico's Under-17 squad for the CONCACAF Championship -- World Cup qualifying -- starting May 1, with head coach Marco Antonio Ruiz denying any suggestion that the former U.S. youth national team player had to be convinced to join El Tri.
"I've heard a lot of comments about it. We didn't have to convince anyone," said Ruiz in a news conference. "Everybody is happy. I never had any problem with Efrain.
"I had a lot of communication with him, I never had to convince him," he added. "I hope I have him at his best and that he can help us win a ticket to the World Cup."
The U17s World Cup will take place in Brazil later in the year.
Goalkeepers: Angel Alonzo (Necaxa), Carlos Higuera (Tijuana), Luis Lopez (Dorados)
Defenders: Kevin Alvarez (Pachuca), Arturo Cardenas (Querataro), Oswaldo Leon (America), Efrain Orona (Pachuca), Gilberto Sepulveda (Chivas), Mario Trejo (Monarcas)
Midfielders: Misael Dominguez (Cruz Azul), Francisco Figueroa (Pachuca), Carlos Gutierrez (Pumas), Diego Hernandez (Chivas), Diego Lainez (Real Betis), Adrian Lozano (Santos Laguna), Roberto Meraz (Monarcas), Jose Plascencia (Necaxa), Alan Torres (Chivas)
Forwards: Roberto de la Rosa (Pachuca), Daniel Lopez (Tijuana), Jose Juan Macias (Leon)