Morata was injured in the first half of Chelsea’s 1-0 Premier League defeat against Manchester City last weekend.
The 24-year-old, who has scored seven goals in nine appearances since joining Chelsea in the close-season, initially joined up with Spain before their World Cup qualifiers against Albania and Israel.
But he withdraw from international duty after an MRI scan showed “a grade II myofascial injury in the hamstring muscles”.
It was feared Morata might be sidelined for up to a month, but Chelsea hope he will be available sooner and the former Real Madrid star has reported for assessment and rehabilitation.
On Tuesday, Morata posted a social media photo of himself in a Chelsea training top, with a target emoji ahead of Crystal Palace, the champions’ next opponents on October 14.
“I have no time to lose! Working hard towards recovery! Crystal Palace,” he tweeted.
