Bad news for Real Madrid. According to several reports coming from Spain (Marca and COPE), Marcelo's presence in Saturday's Derby against Atlético de Madrid is questionable at best. The Brazilian left-back is feeling some muscular problems and while Real Madrid have not released a medical report on his status, it seems that Zidane will not risk a bigger injury on his starting left-back, per those same reports.
If the player isn't feeling 100% ready to go, it would be wise to keep him out of the game considering that the Liga BBVA title is almost in Barcelona's hands already. Zidane will probably start making rotations in La Liga to keep his men fresh for the demanding Champions League games that will be ahead if Los Blancos manage to keep their 0-2 lead to AS Roma.
Either way, Zidane will probably have an update on Marcelo today when he speaks in the pre-match press conference.