Zinedine Zidane believes a suspected hamstring injury sustained by Marcelo is "small", with the left-back potentially a doubt to face Paris Saint-Germain in the Champions League next month.
Marcelo scored Madrid's final goal in a 3-1 win in the French capital but limped out of a thrilling 5-3 LaLiga victory over Real Betis on Sunday.
Madrid are already without midfielder Toni Kroos, the Germany international missing the trip to Betis with an ankle strain.
Both players have less than three weeks to recover in time to face PSG at the Santiago Bernabeu on March 6.
But Zidane is upbeat about the Brazilian's chances of being fit.
"I hope Marcelo's problem is small," Zidane said after his side came from 2-1 down.
"He said his feeling was that it was not too serious. But we will see in the coming days."