Horsman was due to face up to Andrew Sheridan at Twickenham

The 27-year-old is due to undergo an operation on Thursday, and will miss the entire Six Nations campaign.

The news will be a severe blow to Wales, who hoped to have the strong scrummager available to face Andrew Sheridan at Twickenham on 4 February.

Ospreys tight-head Adam Jones - a key member of the Grand Slam squad - is now likely to reclaim his Wales spot.

"Chris has been playing through the pain from his ankle for some time now and the point has been reached where surgery is the only real option," said Worcester director of rugby John Brain.

Chris came through the autumn Tests with flying colours Wales coach Mike Ruddock

"It is a blow for us, but not an unexpected one and we have enough quality props at the club to deal with the situation.

"Until the surgery has been completed we can't be sure exactly how long he will be out of the game, but we'll do everything we can to ensure that his recovery will be complete."

English-born Horsman forced his way into the Wales team in the autumn after qualifying by residency.

His indiscipline was criticised by national coach Mike Ruddock after he was yellow carded at a crucial moment in the defeat to South Africa.

But his power at the set piece impressed, and he played a key role in the landmark victory over Australia.

The contest between Horsman and Sheridan would have been one of the highlights of the England v Wales match this year From 'It used to be muscle' Join the Scrum V debate

"The news comes as a blow to our ambitions to retain the Six Nations title," said Ruddock.

"Chris came through the autumn Tests with flying colours when his positive attitude to the scrummage rubbed off on other players and his work outside the scrum was also impressive.

"We wish him a complete recovery, bearing in mind that we also have him in our mid-to-long-term plans.

"As with all injuries, it is a chance for players to grab the opportunity with both hands and try to hang onto the red jersey if they get it."

Horsman's Worcester colleague Pat Sanderson is struggling with a back injury.

The England flanker is in a race to be fit for the Wales game next month.

Ruddock's team are already without Brent Cockbain, Ryan Jones, Gavin Henson, Tom Shanklin and Kevin Morgan, while Sale have first call on the services of Mark Taylor.