Twice former champion Jennifer Capriati has withdrawn from next week's Australian Open because of an injury to her right shoulder, organisers said on Wednesday.

The American, winner at Melbourne Park in 2001 and 2002, had previously pulled out of this week's Sydney International, having earlier been forced to miss an exhibition match with Wimbledon champion Maria Sharapova on December 17.

The news is a major blow to Australian Open organisers, who were already without injured Belgians Justine Henin-Hardenne and Kim Clijsters, last year's champion and runner-up.

The year's first Grand Slam starts on Monday.