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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