Morata picked up a hamstring injury while on international duty with Spain and is likely to miss a month of first team action.
Real Madrid released Morata's medical report on the club's website, which said: "After tests carried out on our player Alvaro Morata at the Sanitas La Moraleja University Hospital prior to the training session held today, Wednesday, he has been diagnosed with a grade 2 muscle injury in his right hamstring. His recovery will continue to be assessed".
This is likely to come as a blow to Madrid manager Zinedine Zindane as Morata has been in good form for 'Los Merengues' this season, scoring eight goals in 17 games, with half of these coming from the bench.