Marcelo will miss the remainder of the 2019/20 LaLiga Santander season due to an injury to his left adductor.
The Brazilian left-back is expected to be sidelined for around three weeks and Los Blancos hope to have him back and fully fit for the return leg of the Champions League round of 16 tie against Manchester City on August 7.
"Following the tests carried out today on Marcelo by the Real Madrid Medical Services, he has been diagnosed with an injury to his left adductor muscle," read Real Madrid's statement.
"His recovery will continue to be assessed."