FIFA says the compulsory release of clubs' under-23 players for the London Olympics is covered by its existing rules even though the tournament was left off the international match calendar.

FIFA cites its player status regulations that "a duty to release players exists on the basis of a special decision by the FIFA executive committee."

FIFA believes that clause empowered President Sepp Blatter to pass a compulsory Olympic release rule last week.

In 2008, the Court of Arbitration for Sport dismissed a "special decision" that FIFA said its emergency committee made days before the Beijing Olympics.

The court upheld an appeal by three clubs, including Barcelona. The Spanish power initially blocked Lionel Messi from representing eventual gold medalist Argentina.