MADRID, May 22 (Reuters) - Lionel Messi on Thursday put playing for Argentina at the Olympic Games in August ahead of Barcelona's Champions League third qualifying round tie. 'It is up to me to decide and the Olympic Games are something I will never be able to play in again. I am very excited at the prospect,' Messi told a news conference on Thursday. The 20-year-old forward said he had not officially told the club, but did not expect there to be any problems with his decision. 'We don't know who we are going to be playing yet (in the qualifier) but Barcelona don't depend only on me to win games. I think the club and the fans will understand,' he said. Barcelona finished third in the Primera Liga championship that ended last weekend, missing out on automatic qualification for Europe's elite club competition. The 2006 winners will have to play a qualifier on Aug. 12/13 and 26/27 to make the group stage. The Olympic football tournament, which Argentina won at the Athens Games four years ago, takes place from Aug. 6 to 23.