Zinedine Zidane says Marcelo will only play against Roma if he is at full fitness.
"Marcelo will only play if he is 100 per cent. I think he is, but we will see what happens," explained the coach, on the eve of his Champions League debut as a coach.
"He should sleep well and tomorrow we will see, but for a competition and a game like this you have to be at 100 per cent."
Asked about the game, he said: "You have to do the same as we do in La Liga. Roma are a difficult team, and we are away from home, but we had a good week and I am confident to do well tomorrow.
"We want to progress. We will try to give our best and we shall see. We have to be concentrated, the players are, and it is important to me. When I see that, I'm more relaxed."