Real Madrid goalkeeper Thibaut Courtois has sustained another serious knee injury, just as he was close to returning from a torn ACL.

Madrid said Courtois ruptured the meniscus in his right knee during Tuesday's training session. The Belgian has not played since tearing the ACL in his left knee in August, two days before Madrid's first game of the season. He just recently returned to training after recovering from surgery.

Madrid did not give a timeline for how long Courtois will be out this time, saying only that “the injury will be monitored.”