Cristiano Ronaldo cuts training short and leaves with ice pack on knee... so will Portugal's star be fit for World Cup opener?

Cristiano Ronaldo has caused concern in the Portugal camp ahead of their crucial World Cup opener against Germany after leaving training early with an ice pack attached to his left knee.

The Real Madrid maestro is relied upon in the Portugal team, but the 29-year-old's campaign could have taken a hit if the injury that bothered him at Real Madrid has made its way to Brazil.

Ronaldo managed less than 20 minutes with the rest of his team-mates before being forced to leave.

Packaged up: Ronaldo leaves training with ice on his left knee in Brazil on Thursday

Leaving: Ronaldo makes his way off the training pitch after managing 15-20 minutes with the squad

Off: Ronaldo waves his goodbyes to the crowd as he leaves Portugal's training session ahead of everyone else

Ronaldo reportedly signed shirts, met fans and stretched out before taking a seat on the bench while his team-mates continued with their drills.
The 2014 Ballon d'Or winner was out of action for two weeks with tendinitis in the knee before the World Cup - an injury which had been largely kept secret.
A return of that would come as a major blow to manager Paulo Bento so close to the tournament.
It is hoped Ronaldo, who did not look in pain, will be able to start in Portugal's opener but the extent of his fitness is yet to be seen.

Ronaldo cuts short his training with Portugal due to precaution