Juventus midfielder Arturo Vidal was unable to train with his Chile teammates on Monday because of a knee problem, putting his participation in the team's opening World Cup match on Friday against Australia in major doubt.

Vidal underwent surgery to repair a meniscus in May and had to leave the pitch shortly after training began at the Toca da Raposa II complex on Monday with swelling on his right knee.

In his absence, coach Jorge Sampaoli tried out both Jean Beausejour and Felipe Gutierrez as possible midfield replacements for the Juventus star.

After facing Australia, Chile takes on defending World Cup champion Spain and 2010 finalist the Netherlands in Group B.