A statement issued by world football's governing body FIFA have confirmed the judge of the Players' Status Committee, Slim Aloulou, agreed with FIFA's previous ruling that it was "mandatory" for players to be released for Olympic duty.
The judge was called to rule on the matter after Werder Bremen, Schalke and Barcelona questioned FIFA's stance as the Olympics do not appear on FIFA's official calendar.
Bremen and Schalke are unhappy with the inclusions of Diego and Rafinha, respectively, in the Brazil squad, while Barca are trying to prevent star forward Lionel Messi joining up with Argentina.
The Court of Arbitration for Sport will now have the final say on the matter after Bremen and Schalke filed complaints, with Barca having indicated they will do likewise.