Real Madrid goalkeeper Thibaut Courtois has suffered a torn ACL in his left knee and will undergo surgery in the coming days, the Spanish club announced on Thursday.

Sources have told ESPN that with Courtois out for six to seven months, Madrid will look to sign a new goalkeeper to deputise while the Belgium international is sidelined.

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Courtois was injured during Thursday morning's training session.

"After the tests carried out on our player Thibaut Courtois, he has been diagnosed with a torn anterior cruciate ligament in his left knee," a club statement said. "The player will undergo surgery in the coming days."

The club did not confirm how long Courtois will be sidelined for but according to reports in Spain, the former Chelsea and Atletico Madrid goalkeeper will be out for at least six months.

This is the first serious injury sustained by Courtois in his career.

Courtois, 31, played 43 games across all competitions for Madrid last season, his fifth campaign with Los Blancos.

Andriy Lunin is set to replace Courtois as Madrid's No. 1 but sources have told ESPN, the Spanish giants are looking to sign a keeper before the transfer window closes on Sept. 1.

Madrid begin LaLiga on Saturday away to Athletic Bilbao.