La Liga's hopes to have a regular-season game staged overseas every year had a setback on Friday after the Royal Spanish Football Federation (RFEF) sent a letter to La Liga stating that they do not support a plan to play in Miami.
La Liga president Javier Tebas confirmed receipt of the letter, but reiterated his optimism.
"We have read the letter, which is pretty long. Obviously [the RFEF] aren't excited about [a match in Miami]," Tebas told reporters. "They are not saying no, they are just requesting more information. I have been talking about this for some time now, so I am optimistic."
The RFEF received a formal request from La Liga, Girona and Barcelona earlier this month detailing plans to move a game to suburban Miami on Jan. 26 as part of a 15-year agreement with Relevent Sports to market the league in North America.
It has not finalised its stance on the proposal, but on Friday, it sent different letters to La Liga, UEFA, FIFA and the two clubs.
"In the letter sent to FIFA, the RFEF has explained its intention not to authorise the game," the organisation told ESPN FC.
Moreover, in the letter addressed to UEFA and FIFA, the RFEF requested the governing bodies share their recommendations regarding the implications of staging a La Liga game outside of Spain.
The RFEF notified La Liga that it is consulting with both organisations regarding which rules could be infringed if a league game was to be played abroad. It also requested La Liga present documents to show it has the approval of the necessary organisations as well as of all top-flight clubs -- not just Girona and Barcelona -- and has demanded more information regarding the set-up of the game.
It also reminded La Liga that a change of venue would affect television contracts and club members and could see certain teams benefit while others would be affected.
La Liga need the support of the RFEF as well as Spain's Sports Council, UEFA, CONCACAF and U.S. Soccer in order to move the game away from Girona's Estadi Montilivi.
Tebas insisted that the RFEF is not saying the match cannot happen, but they are simply requesting more information.
"What they are asking us for is more documentation," Tebas said on Friday. "A committee has been meeting all morning and I have not had time to really study the letter they sent. It is pretty extensive. We are going to prepare something for them and we are pretty optimistic.
"If [reporters] would like, I can read you what it says at the end. Because of course, when the letter leaked out and [reporters] said that [the RFEF] don't authorise a match ... I am going to read you the last part of the letter.
"'We confirm that we have received your request [to play in Miami], but we cannot move forward with the request until you provide us with the documentation that clears up your request and guarantees that all the legal precepts and regulations have been duly met. This is necessary in order to meet the agreement for rights, and the regulations and criteria from FIFA and UEFA as we are interpreting it.'"
Tebas told reporters: "So you can see, they are not saying no, rather they are asking for further documentation to clear up the question of rights. But it is clear to me that they do not want to give approval, that much I can see.
"I still believe there is a 90 percent chance that the game will go ahead. Even if we had gotten a no, it's not going to stop us and we will fight because the game will be played in Miami on Jan. 26. The game will go ahead. Nothing has changed.We believe we are in the right."
FIFA, according to Tebas, does not have a say on the matter, but has already expressed reservations regarding the location change.
The RFEF's stance comes just 24 hours after the Spanish Footballers' Association (AFE) said it remains unconvinced that plans to hold a game in North America each year are in its best interest.
AFE insisted that La Liga had taken a unilateral decision without consulting the players and that their plans to play outside the country breached several articles of the collective agreement between the two entities.
Tebas told ESPN FC earlier this week that it would be hypocritical of the RFEF to turn down La Liga's petition considering the Spanish Super Cup between Barcelona and Sevilla was played last month in Morocco.