The Association of Spanish Footballers (AFE) has confirmed its formal opposition to LaLiga's plan to play Girona's home game against Barcelona in Miami.
Both clubs have agreed to the proposal, which comes as part of a deal with Relevant, the company behind pre-season tournament the International Champions Cup.
LaLiga matches will be played in the United States across a 15-year period under the terms of the agreement, with Girona-Barcelona slated for January 2019.
But players have signalled their opposition to the scheme, while Real Madrid president Florentino Perez indicated Los Blancos would refuse to take part in a match outside of Spain.
The Royal Spanish Football Federation (RFEF) has asked for more documentation from LaLiga over the proposal, but the league's president Javier Tebas still believes the match will take place in Miami.
The AFE previously threatened strike action over the Relevant deal and on Monday the organisation confirmed it will not give the green light to the Miami plan.
A statement read: "The AFE want to express the following after receiving a more detailed report on the game between Girona and Barcelona which LaLiga hopes to move to the United States in 2019:
"1. We have informed LaLiga that said report does not specify the specific and necessary objective elements to be able to determine that the provisions of Articles 8, 9 and 37 of the Collective Bargaining Agreement will not be violated.
"2. The AFE reminds [LaLiga] that for the time being, there are no mandatory authorisations that allow for the game to be played in the United States.
"3. For that reason, considering the lack of information mentioned, the AFE has transmitted to LaLiga its lack of support for that decision."
AFE additionally confirmed the body will not consider changes to its agreement with LaLiga until 2020.
RFEF leader Luis Rubiales opposes the Relevant deal, describing as an "invasion" of the United States, but Tebas has cited the precedent of this season's Supercopa de Espana between Barca and Sevilla being played in Morocco.