Marcelo has handed Zinedine Zidane a new concern after suffering a muscle injury during Real Madrid's 1-0 defeat to Real Betis - which leaves Los Blancos seven points adrift of leaders Barcelona after only five La Liga games.
The Brazilian left-back returned to Zidane's line-up on Wednesday night (20 September) after missing the previous victory over Real Sociedad due to suspension.
However, he was forced off and replaced by Lucas Vazquez in the 72nd minute of the match after picking up a muscle problem.
"I have pain in my leg. We'll see after scans," Marcelo confirmed to the reporters before expressing his frustration with the defeat.
"We gave it our all, tried to score but in the end, we conceded when really we were looking for three points. There is plenty of time to improve and we have come out of tougher situations on top. We'll keep working as always. Adán was brilliant for Betis, making some key saves,
The team looked good to me and I thought we were better than Betis, but it is the result that counts in the end. I'd prefer to play badly and get the win. We had more possession, had shots on goal, but football is like that at times. Last year we won games we maybe shouldn't have, and this year it is the other way around. That can happen. There is no need to go crazy, we will work hard and turn this around."
Zidane will be sweating on the results of Marcelo's scan as Real visit Alaves on Saturday [23 September] three days before the Champions League trip to Borussia Dortmund.
Marcelo's potential absence for those games would be a major blow for Zidane as reserve left-back Theo Hernandez is already on the treatment table alongside Karim Benzema, Jesus Vallejo and Mateo Kovacic.
Theo suffered a "partial dislocation of the right shoulder" during the weekend win over Real Sociedad and reports in Spain are suggesting that he could be out of action for around two weeks.
The injury situation adds to Zidane's concerns following a disastrous start to La Liga which has left them seven points behind leaders Barcelona after only five games.
Real Madrid have eight points from their opening five games of the season, having drawn with Levante and Valencia at home before losing to Betis on Wednesday after conceding a goal in the 94th minute of the game.
Barcelona, meanwhile, have won all their games but Zidane has backed his side to turnaround the situation and believes that there is no reason to panic.
"It's tough to lose Marcelo and concede the goal. Perhaps we didn't deserve to win the game, but we definitely didn't deserve to lose it. I know that a lot of people don't like to hear that when things are going badly, but we've got to accept it, remain calm and focus on the next game. La Liga is a long competition and we're going to make sure there is a sense of calm in the group because we'll recover from this and I'm sure we'll have better days," Zidane said.
"The way we see it, is that the ball just didn't want to go in today. We had 26 or 27 attempts and in the end, it hasn't gone in. That's football. It wasn't a great performance but it wasn't too bad either. If you get a goal, it's a different game. Last year we won games that perhaps we didn't deserve to win, now it's gone the other way. We have to stay calm. That's three games at home and we've taken two points from nine."