FIFA ruled Wednesday that clubs are obliged to release players aged 23 or under for the Beijing Olympics, clearing the way for Lionel Messi to play for Argentina despite opposition from FC Barcelona.
Slim Aloulou, a Tunisian judge on FIFA's player status committee, said the release of under-23 players was "mandatory for all clubs."
"Taking part in the Olympic Games is a unique opportunity for all athletes of any sporting discipline," FIFA said in a statement. "It would not be justifiable to prevent any player younger than 23 from participating in such an event if his representative team had qualified."
Barcelona said in a statement it would appeal the decision.
"FC Barcelona will shortly present before the CAS, or Court of Arbitration for Sport, an appeal against this decision in which it will request the ruling be rescinded and that proceedings be completed with the maximum speed possible," the club said.
Barcelona president Joan Laporta said he would be meeting with Messi to discuss the matter.
"At this stage we are at an impasse. We are going to meet with Messi to take the most convenient decision for both sides," Laporta said. "I understand our actions to be very respectable within a sporting background. If the CAS's decision is also favorable then our aspirations will have to be accepted."
Laporta said Barcelona did not want to jeopardize Messi's interests but would pursue a decision in its favor aggressively.
"We had anticipated Messi would travel with us to the United States," Laporta said. "What we can't do is jeopardize the player's interests. ... We understand it is very complex to retain a player. Messi will do what the rules say and I understand these will be interpreted in favor of Barcelona by CAS.
"What would normally happen now is for the player to go to play with Argentina but if CAS finds in favor of Barcelona, he'll have to come back," Laporta said.
Apart from the 21-year-old Messi, the decision means that Schalke and Werder Bremen must release Rafinha and Diego, respectively, for Brazil.
The three clubs had challenged the FIFA rules, saying the Olympics were not included on football's international match calendar.
But FIFA said the calendar only reflects the schedule for A teams — those which include players older than 23. The dates for the Beijing tournament are set by the International Olympic Committee, and not by FIFA, it added.
The release of young players has traditionally been accepted by clubs since the rule first came into force 20 years ago.
A FIFA emergency committee separately confirmed the rule Tuesday.
Prior to Wednesday's ruling, Barcelona had indicated it would go to CAS if the FIFA ruling went against it.
Messi added he would return to Barcelona if CAS then ruled in its favor.
"Barcelona continues with its stance of not wanting to let me go and I understand it," Messi said. "But I also think they have to understand that my dream is to take part in the Olympic Games with the national team."
Barcelona and Schalke both have Champions League qualifiers during the period of the Olympics.
The Olympic tournament will begin one day before the Aug. 8 opening ceremony.