West Brom have announced that Chris Brunt will be sidelined for eight to ten weeks with a fractured right ankle.
The Northern Ireland international suffered the injury when he landed awkwardly during the closing stages of the New Year's Day defeat by Everton.
Scans have now revealed the extent of the damage and Brunt will undergo surgery on Friday before beginning his rehabilitation at the club's training ground next week.
He faces a long road back to fitness as he is not expected to return to action until around the middle of March.
News of the captain's lay-off will come as a major blow to manager Roy Hodgson, who had feared it was a serious problem.
Hodgson is also set to be without Shane Long for another fortnight despite the striker having an injection to ease his back problem.
The Republic of Ireland international was ruled out of the midweek loss at Tottenham and is also set to be on the sidelines for the FA Cup tie with Cardiff and the Premier League encounter with Norwich.
Long is the Baggies' joint top scorer with five goals this season after his summer move from Reading.
He told the Express and Star: "I had an injection yesterday to speed things up but it's very tender at the moment. I'm not training.
"Hopefully it's only going to take a week or two and it's no more serious than that.
"The injection is designed to kill the pain so I can start on my rehab. I'm going to try to aim to be fit for the Norwich game, but that might be a bit too soon."