Madrid - Spanish giants Real Madrid announced on Sunday morning that Daniel Parejo would be out of action for around a month after twisting his left knee in training.
Parejo, 19, suffered the injury on Friday, in a training-ground clash with veteran Guti.
Parejo, a Spanish Under-21 international midfielder, has just returned to Real after a five-month loan spell at London club Queens Park Rangers.
He was expected to feature in Sunday's league game at home to Villarreal, together with new signings Klaas Jan Huntelaar and Lassana Diarra.
Real have signed Huntelaar and Diarra because of their injury crisis, though only one of them can be registered for the knockout stages of the Champions League.