Paraguay striker Roque Santa Cruz is a doubt for his country's World Cup campaign after admitting that he is still struggling with the knee injury he suffered nine months ago.

The 24-year-old Bayern Munich star sustained a cruciate ligament injury to his right knee in October last year and felt a twinge while training at Paraguay's Austrian training camp in Flachau.

"I felt pain in the knee and it was not a nice feeling," he told Bild am Sonntag.

Santa Cruz has been a regular in the Paraguay side for the last six years and moved to Bayern Munich from Olimpia in 1999.

However, a series of injuries have dogged his time in the Bundesliga and he has never scored more than five goals in a season for the German giants.