Jude Bellingham suffered an injury during Sunday's match to the semitendinosus muscle in his left leg.
This means the Stourbridge native will be sidelined for about a month, missing Real's upcoming league matches as well as the Champions League tie against Benfica.
He will definitely miss the first leg, and the second leg looks highly unlikely.
It was the ninth minute of the match when the British player was unable to finish a sprint. He grabbed his thigh, signalled for a substitution, and was immediately replaced by Brahim Diaz.