Gloucester wing James Simpson-Daniel will have an operation on his left shoulder next Wednesday while centre Will Greenwood may miss the entire tournament after also undergoing shoulder surgery.

England are already without flanker Richard Hill for the whole of this season due to a serious knee injury, while Greenwood's World Cup centre partner Mike Tindall is struggling with a foot problem.

And fly-half Jonny Wilkinson, a strong candidate for the inside-centre berth against opening RBS 6 Nations opponents Wales on February 5, has not started a game since mid-October following a bicep injury.

Elsewhere, World Cup props Trevor Woodman and Phil Vickery have hardly played this season, in addition to several players announcing their retirement from Test rugby throughout 2004, so Robinson has his hands full ahead of a debut RBS 6 Nations tournament as red rose boss.

Harlequins star Greenwood, capped 55 times, underwent an operation on his right shoulder yesterday after experiencing ''low grade'' pain for the past 12 months. He left hospital today.

He is unlikely to be regain full match fitness for four months, while the length of Simpson-Daniel's absence will not be known until after he goes under the surgeon's knife.

''It is disappointing to hear of the injuries to these world-class players,'' said England head coach Andy Robinson.

''But I am pleased to note their progress has so far been positive. It is a cause for concern that there appears to be more injuries at this level, and it is important we all protect the welfare and longevity of every professional player.''

Greenwood has struggled for form this season and was on the bench throughout England's autumn series of Tests against Canada, South Africa and Australia.

But the 32-year-old boasts an outstanding try-scoring record against Wales and Robinson might have been tempted to start with him at the Millennium Stadium.

Tindall, meanwhile, is battling to overcome a foot injury which early forecasts suggested would not heal in time for the Cardiff showdown.

And with Gloucester centre Henry Paul facing an uncertain international future following his 26th-minute substitution during the November defeat against Australia, Robinson is set to field a new midfield combination.

It is understood he is considering Wilkinson for an inside-centre role in Cardiff, leaving Wasps' Stuart Abbott, Leicester prospect Ollie Smith and Newcastle's Jamie Noon as leading contenders for the number 13 jersey in Tindall's possible absence.

One rabbit out of the hat though would be to switch Jason Robinson from full-back to centre, where he started last season's RBS 6 Nations campaign.

Simpson-Daniel, meanwhile, must come to terms with his latest setback during a career dogged by injuries and illness.

''I have just got to get on with the operation next week and see how the results go,'' he said.

''It is so frustrating, and the last few weeks have been really tough.''