On-loan West Ham United midfielder David Bentley has been ruled out for six months after undergoing surgery on his knee.
Bentley joined from Tottenham Hotspur on transfer deadline day but, after exploratory keyhole surgery revealed a problem on Tuesday, he is now expected to be out until the final weeks of the campaign.
Bentley has now returned to parent club Spurs to continue his rehabilitation.
"It is a great shame for David as he had settled in well to the squad," Hammers boss Sam Allardyce told the club's official website. "We wish him well and hope he has a speedy recovery."
A Tottenham statement added: "David Bentley has undergone surgery to his left knee. The right-sided midfielder, who joined West Ham United on loan in August, is likely to be out for up to six months."
Bentley made five appearances for West Ham, who currently lie fourth in the Championship, and started the club's last two games.