Real Madrid striker Karim Benzema could be out of action for up to three weeks after suffering a hamstring strain.
The Frenchman did not feature in Madrid's training session on Saturday and underwent a medical examination instead, having made an early exit in a 3-0 loss to Barcelona on December 23.
Madrid's tests subsequently confirmed a hamstring problem, and while the club have not released a timetable for his return, reports suggest he is expected to be out for two to three weeks — a period that would potentially feature five games across the Copa del Rey and La Liga.
Benzema has scored five goals in 18 matches in all competitions for Madrid this season.
The Clasico defeat has left Los Blancos fourth in La Liga entering the new year, 14 points back of first-placed Barca.