Real Madrid ace Ronaldo struggling to make World Cup opener
Ronaldo is struggling with tendonitis around his left kneecap, the national federation have revealed.
Real president Florentino Perez earlier urged the national team not to risk the 29-year-old if he was not fully fit.
He told Cadena SER: "I am concerned that any player can pick up a serious injury, as has happened (in the past) with Kaka and (Sami) Khedira.
"A player like Cristiano Ronaldo should only play if he is fit."
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