DOHA, Qatar (AFP)— France forward Karim Benzema is to undergo medical tests after leaving training injured on Saturday ahead of the defending champions World Cup opener against Australia.

The Real Madrid striker has been struggling with a thigh problem since October and has played less than half an hour of football in his club’s last six games.

The 34-year-old’s return to full training was curtailed by the injury with tests later Saturday due to determine its nature and seriousness, a source close to Les Bleus said.

This was the first time Benzema had taken part in full training since Didier Deschamps’s squad met up at their French headquarters of Clairefontaine last Monday.

Under FIFA rules Deschamps can call up a replacement for an injured player until Monday, on the eve of their first game against Australia.

Doubts over Benzema’s fitness is a major headache for Deschamps, already deprived of the services of midfielders Paul Pogba and N’Golo Kante, number two goalkeeper Mike Maignan, defender Presnel Kimpembe and forward Christopher Nkunku.

Benzema, who last month won the Ballon d’Or, has not played an entire match since October 19.

He and Raphael Varane trained apart from the rest of the squad on Thursday during a session open to the media at the home stadium of Qatari champions Al Sadd.

Manchester United centre-back Varane has not played a game since coming off in tears against Chelsea on October 22.