Soccer's governing body FIFA has ordered clubs to release Under-23 players called up by their national teams for the Olympic Games soccer tournament.
The move, approved by FIFA's executive committee on Friday, is potentially controversial as the competition is not part of the international match calendar.
"The executive decided that the release of under-23 players by the clubs shall be compulsory," FIFA said in a statement.
The 2008 Olympic soccer tournament was marked by a tug-of-war between Barcelona and Argentina over the release of Lionel Messi, which went to the Court of Arbitration for Sport (CAS).
CAS ruled in Barcelona's favour but the Catalan club then decided to release him in any case.
The Olympic soccer tournament, which clashes with the European pre-season, is restricted to under-23 players although each team can field upto three overage players.
The soccer tournament at London 2012 kicks off the competitive action at the Olympics on July 25.
