Real Madrid midfielder Mahamadou Diarra is set to be sidelined for two months with a knee injury.
The Mali international has been struggling with a knee problem he sustained on international duty in October.
Diarra is due to undergo surgery and the 27-year-old confirmed he will be out until the first knockout round of the UEFA Champions League, which commences in February.
He told skysports.com: "I am disappointed. I think I should be back for the Champions League knockout stage."
Meanwhile, Real have explained that a heart anomaly is likely to have caused Ruben de la Red to collapse during a match in October.
However, the director of Madrid's medical services, Carlos Diez, said a more definitive diagnosis on the health of the 23-year-old Spain international would be made after the results of a genetic study were known.
He said on the club's official website: "I know I'm in good hands. My mood is fine, I'm calm and of course I'm very keen to help my team-mates. But I must be realistic and take the situation calmly.
"First I must think about Ruben the person, about my health, and then about De La Red, the footballer. I'm convinced of that."