Crystal Palace manager Roy Hodgson has revealed that Ruben Loftus-Cheek could be sidelined for the rest of the season with an ankle injury.
The on-loan Chelsea midfielder has not featured since December 28 due to what was thought to be a minor injury.
Hodgson has now admitted that the damage to Loftus-Cheek's ankle is more serious than originally believed and is unsure whether the England international will be fit in time for the World Cup.
"The injury is more severe than we originally thought, or perhaps hoped, it would be," Hodgson told BBC Sport. "I would be very disappointed, surgery or no surgery, if he's not playing before the end of the season.
"We certainly want him to be and I would presume Chelsea would want him to be because they might like to have a player who's going to be selected for England in their squad but there's literally nothing we can do about it. The only way he can make himself available for Crystal Palace or England is to be fit and at the moment that isn't the case."
Asked whether Loftus-Cheek could be a doubt for the World Cup in Russia, which kicks off on June 14, Hodgson replied: "I don't know. I don't want to go into that at the moment because we don't know how long it would take after surgery to get him fit again."
The 21-year-old was handed his international debut by England boss Gareth Southgate against Germany at Wembley Stadium in November, followed by a second cap in the subsequent meeting with Brazil.