Karim Benzema missed Real Madrid's open training session on Tuesday, casting further doubt on his chances of facing Manchester City.
The France international was taken off at half-time of the first leg of the Champions League semi-final with a hamstring problem and also sat out the Liga win over Real Sociedad last weekend.
Head coach Zinedine Zidane said last week that he was hopeful of having his compatriot ready for City's visit to the Santiago Bernabeu on Wednesday, though that now looks to be far from certain after he sat out Tuesday's early session.
Benzema had trained alone on Sunday in a bid to prove his fitness prior to this week.
Cristiano Ronaldo, however, took part in the full session, having resumed training duties at the weekend following a hamstring injury which kept him out of the first leg, which finished 0-0.
Casemiro, who picked up a knock in Saturday's win at Anoeta, also missed the session.