كتب : Omar AbdelAziz
The Dutch striker has been recently struggling with a troublesome ankle, where he underwent external meniscus surgery in 2000.
Top Spanish football newspapers Marca and AS reported that the 32-year-old is set to go under the knife in the near future.
Real have confirmed that Van Nistelrooy aggravated the old injury, and that he will consult American specialist Richard Steadman in that matter.
Van Nistelrooy's injury will be a massive blow for the Spanish champions, who might be looking for a replacement to their top marksman in January.
The names of Karim Benzema, David Villa and Mario Gomez have been mentioned as possible targets for the Madridista in the winter break.