La Roja now lead Group G by three points ahead of Italy.
Many questions were raised when the Blues chose the £70-million Morata to replace the outgoing Diego Costa, considering the fact that the Spanish global had never managed to really establish himself as a first-team regular at Real Madrid.
Spain conducted their own tests on the 24-year-old on Sunday at the Sanitas University hospital of La Moraleja in Madrid, where a scan apparently revealed the myofascial injury. I don't think it's serious. He said he would prefer to stop and not risk a bad injury.
Chelsea have been dealt a major blow after the Spanish Football Federation claimed striker Álvaro Morata has suffered a grade two hamstring injury that could rule him out for over a month.
Chelsea will now monitor Morata's recovery and hope that he is fit to face Crystal Palace on October 14. Lopetegui has named Athletic Club Bilbao striker Aritz Aduriz to replace the Chelsea number nine.