(CNN) -- A FIFA ruling on Wednesday has cleared the way for Argentina playmaker Lionel Messi to represent his country at the Beijing Olympics.
Messi has been training hard ahead of the new season with Barcelona.
Messi's club Barcelona and Bundesliga sides Schalke and Werder Bremen had challenged the world governing body over their insistence that players aged 23 and under must be released to play in the Games.
The clubs also claimed that the dates of the Beijing football tournament, from August 6-23, were not part of football's international calendar.
But Slim Aloulou, a Tunisian judge on FIFA's player status committee, confirmed that 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."
Apart from the 21-year-old Messi, the decision means that Schalke and Werder Bremen must release Rafinha and Diego, respectively, for Brazil.
Barcelona have said they would take their case to the Court of Arbritration in Sport (CAS) if FIFA ruled against them, clearly concerned about the loss of Messi for a crucial Champions League qualifying tie.
Messi, who would be the star attraction in a strong Argentina side, told the Barcelona club Web site that he would honor any subseqent ruling by the CAS.
"Barcelona are continuing with their stance of not wanting to let me go and I understand it," Messi said. "But they have to understand that my dream is to take part in the Olympic Games with the national team."
Messi's former Barcelona teammate Ronaldinho will play at the Olympics as an over age player for Brazil. Clubs are not obliged to release this category of player for the Games, but Ronaldinho's new club AC Milan say the tournament will help him get match-fit for the Serie A season.
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