Real Madrid have confirmed that Jesus Vallejo is set for a spell on the sidelines after sustaining a hamstring injury.
The defender picked up the problem during the first half of Thursday's 1-0 Copa del Rey quarter-final first-leg win at Leganes.
Vallejo was replaced by Nacho Fernandez in the 15th minute and the Spain Under-21 international's recovery will continue to monitored.
"Following the tests carried out today on our player Jesus Vallejo at the Sanitas La Moraleja University Hospital, he has been diagnosed with a muscular injury to his right hamstring," read a brief Madrid statement.
"His recovery will continue to be assessed."
The Spanish and European champions, a mammoth 19 points behind LaLiga leaders Barcelona, host Deportivo La Coruna on Sunday.
