Real Madrid goalkeeper Thibaut Courtois is set to miss one of the most important matches of the season.

The shot-stopper started for Los Blancos during the week in a UEFA Champions League victory against RB Leipzig, but the club announced Sunday that Courtois had to withdraw from the squad hours before the El Clásico rivarly tilt with FC Barcelona.

The Belgian has of a case of the flu he wasn't able to overcome to be fit enough to be part of the roster. Reports from Madrid indicated that he traveled to the team's training ground Sunday morning in hopes of feeling good enough to make the trip, but ultimately the goalkeeper and medical staff opted against the risk.

Who will start instead of Thibault Courtois for Real Madrid?

Illia Voloshyn was added to the roster in Courtois' place, with the Ukrainian teenager serving as an emergency option in case backup Sergio Mestre or likely starter Andriy Lunin suffer an injury.

Lunin played in many of the team's summer friendly matches and also saw 540 minutes of action last season when Courtois suffered a March 2026 quadriceps injury.

Real Madrid already knew it would need to replace winger Vinicius Jr., who is suspended for this match as part of a four-game ban for pulling an opponent's hair. Now, Jose Mourinho also will not have the comfort blanket of Courtois.

The rest of the Madrid squad flew from the Spanish capital to Barcelona on Sunday morning, heading to the hotel where they are staying to rest and prepare for the match.

FC Barcelona leads La Liga, holding a six-point advantage on Real Madrid. The chance to close some of that gap puts huge pressure on a match that already is one of the most pressure-packed matches in European soccer.