Chelsea striker Christopher Nkunku will be out for "an extended period" after undergoing surgery on his injured knee.
The France forward, 25, suffered the problem during the first half of Chelsea's pre-season friendly against Borussia Dortmund in Chicago last week.
Blues boss Mauricio Pochettino said at the time he hoped the injury would not be a "big issue" for his £52m striker.
Chelsea, who host Liverpool in their Premier League opener on Sunday, have not specified a length of absence.
More to follow.
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