Norwich and Wales striker Rob Earnshaw will not return before the end of April after a groin operation on Tuesday.
Earnshaw joined from West Brom for £3.5m in January 2006
The 25-year-old, the Canaries' top scorer with 17 this season, suffered the injury in training last week.
"The injury is similar to that suffered by Robert Green before the World Cup, where the ligament comes away from the bone," said Norwich boss Peter Grant.
"I'd be delighted if he was back by the end of April, but it could be all season. Rob's gutted - as am I."
Wales will lose the 32-cap man for a Northern Ireland friendly next month, plus Euro 2008 qualifiers with the Republic of Ireland and San Marino.
He may also miss the qualifier against the Czech Republic in June.
There are also worries about West Ham and Wales defenders Danny Gabbidon and James Collins for the 6 February friendly in Belfast.
Born: Zambia, 6/4/1981
Clubs: Cardiff, Morton (loan), West Brom, Norwich
Internationals: Has 12 goals in 32 caps for Wales
Left Cardiff for West Brom in a £3m move in 2004. Cost Norwich £3.5m when they signed him in January 2006
He has 18 goals this season (one for Wales)
Gabbidon (hamstring) and Collins (groin) were injured in Saturday's 3-3 draw with Fulham.
Long-term injuries Mark Delaney, Mark Jones and Owain Tudur-Jones are definitely out.
Earnshaw left West Brom for Norwich last January in a £3.5m deal amid a public fall-out with the then-West Brom manager Bryan Robson.
His success at the Canaries had seen him linked with a return to the Premiership in the current transfer window, Portsmouth and Sheffield United both thought to have been interested in the former Cardiff City man.
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