Real Madrid have confirmed that Sami Khedira has undergone an "arthroscopic revision" of his left knee.
The Germany international had already been sidelined by a hamstring injury that he suffered during his side's 4-2 defeat to Real Sociedad late last month.
As a result, the 27-year-old has taken the opportunity presented by his absence to correct a problem in his knee, which is not the same one that he damaged in November 2013.
Los Blancos have not put a date on the midfielder's expected return to action.
