West Ham striker Andy Carroll has been ruled out for three months after undergoing surgery on a foot injury this week.
Carroll, 29, is believed to have sustained a hairline fracture on his foot during the Hammers' 2-1 win over West Brom earlier this month.
The Daily Telegraph reported that Carroll is devastated by the setback, with Chelsea turning elsewhere in their search for a new striker after news of his injury broke.
The England forward has scored two goals in 12 league appearances for West Ham this season.
Speaking before the Hammers' Premier League clash against Bournemouth over the weekend, manager David Moyes described losing Carroll as a big blow for the club.
"We found out yesterday after Andy went for a scan and it showed up that he has got a problem," Moyes was quoted as saying by the BBC. "We are not sure whether the ankle will need an operation or not.
"We are getting two or three specialists to look at it and then we will be able to make the correct decision. Hopefully, we will know within a week.
"To lose him takes away a big part of our armoury," Moyes added. "It is frustrating for Andy, but it is frustrating for us.
"Andy gives us another option and alters the way other teams play against you."
West Ham also fear that Manuel Lanzini could be out of action until February after he picked up a hamstring injury in the 1-1 draw with Bournemouth.
Forwards Javier Hernandez, Andre Ayew and Diafra Sakho have all been linked with moves away from the London Stadium, with Sakho seen as the likeliest to leave this month.
West Ham are in 11th place in the Premier League table, four points above the relegation zone.