Chelsea have been dealt a blow after the Spanish Football Federation said Álvaro Morata had sustained a myofascial injury to his hamstring muscles, an injury which could keep the forward out for more than a month.

Morata, who has scored six goals in seven Premier League games for his new club, pulled up 10 minutes before half‑time in the 1-0 defeat by Manchester City at Stamford Bridge on Saturday, complaining of discomfort in his left thigh.

Antonio Conte suggested Morata’s withdrawal had been precautionary and an attempt to ensure he did not sustain a more serious complaint. He added post‑match that he envisaged Morata pulling out of the Spain squad in order to undergo treatment at Cobham.

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. That implies the damage has not been sustained to the tendon or any ligaments but to the area immediately around the muscle, with recovery time usually between four to six weeks.

Chelsea will undertake their own checks but will fear the worst and the loss of their £60m signing at such a busy period of the season would be untimely. The Premier League champions travel to the bottom-placed Crystal Palace after the international window, but over the subsequent 22 days they face a further six matches.

Those games include both Champions League ties with Roma, as well as matches against Watford, Bournemouth and, most significantly, Manchester United on Bonfire night. Morata would not have been expected to play in the Carabao Cup fourth-round tie at home against Everton.

Michy Batshuayi, the other recognised senior striker on the books after Diego Costa’s departure for £57m last week, has scored five goals this season including the winner at Atlético Madrid last Wednesday. Yet when Morata pulled up on Saturday, Conte had chosen to fling on Willian in his stead, which perhaps reflects Batshuayi’s standing.

Morata, who had limped away from the Champions League tie in Madrid last week with a knock, joined Andrés Iniesta and Dani Carvajal in withdrawing from Spain’s squad for the World Cup qualifiers against Albania and Israel, with Athletic Bilbao’s Aritz Aduriz, 36, Álvaro Odriozola and Jonathan Viera called up as replacements.