Real Madrid's woes deepened on Monday when tests confirmed Brazil fullback Marcelo damaged a thigh muscle in Saturday's 4-0 defeat to Barcelona in the La Liga 'Clasico'.
Marcelo, who had to come off in the 59th minute of the humiliating reverse at the Bernabeu, has not been included in the squad for the trip to play Shakhtar Donetsk in Champions League Group A on Wednesday.
Real did not say how long he might be sidelined but local media reported he would be out for two or three weeks.
Real captain and centre back Sergio Ramos was also left out of the squad for the Shakhtar game, when the 2014 winners and record 10-times continental champions can make sure of top spot in the section having already qualified for the last 16.
Ramos, a Spain international, has been struggling with a shoulder injury but played the whole of the 'Clasico'.
Real coach Rafa Benitez, under pressure after the drubbing from Barca, is taking just five recognised defenders to Ukraine.
Pepe is likely to start alongside Raphael Varane in the middle, with Daniel Carvajal and Nacho at right and left back respectively.