The Spain worldwide limped off during Chelsea's 1-0 defeat against Manchester City on Saturday evening.
Chelsea have been dealt a huge blow in their bid to retain the title, after Alvaro Morata has been ruled out for six weeks.
The Spanish Football Federation have this evening confirmed that Alvaro Morata has suffered a myofascial injury to his hamstring muscles, potentially ruling him out for up to six weeks.More news: Airport chaos as computer check-in systems crash worldwide
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Other experts say Morata could face eight weeks out, but Chelsea have still not placed an official time frame on his comeback.
To play seven games in just over four weeks after the worldwide break will be a big ask for the Belgian, and Antonio Conte will be hoping he can stay fit and fresh during that period.
Tellingly, Conte opted to replace Morata with Willian against City which only increased theories that he does not trust Michy Batshuayi in big games.
Conte is now left desperately short of forwards as he attempts to guide his side back towards top spot in the Premier League after falling six points behind leaders City.