Phil Vickery - struggling with knee injury. (Allsport)

By Andrew Baldock, PA Sport Rugby Union Correspondent

Johnson could miss Australia clash
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England could lose a third injured Lion for the Lloyds TSB Six Nations Championship Grand Slam bid against Ireland in Dublin.

Captain Martin Johnson and back-row giant Lawrence Dallaglio are already out of the Lansdowne Road clash.

And tighthead prop Phil Vickery might now join them after hurting his knee during Gloucester's Premiership victory over Harlequins two days ago.

"At the moment, it is not looking good," said 21-cap Vickery, whose right knee was strapped following prolonged first-half treatment but he finished the game as Gloucester triumphed 33-7.

"I was in agony on Sunday and it got worse as the day went on. Naturally, it is very disappointing."

The England squad began assembling at their base north of Dublin on Monday after flying in from various regional airports.

And manager Clive Woodward is certain to require urgent fitness bulletins, not only on Vickery, but fellow prop Julian White and Leicester forward Martin Corry.

White, the obvious replacement if Vickery is sidelined, sat out Bristol's league defeat at Newcastle on Sunday because of a knee problem, so Woodward could even find himself starting a critical week by summoning front-row reinforcements.

Leicester's vastly-experienced Darren Garforth would fit the bill should Vickery and White both miss the boat, although there is an option in switching Jason Leonard from loosehead and drafting in another Tigers prop, in-form Graham Rowntree.

Ben Kay, Steve Borthwick and Simon Shaw are all vying to fill Johnson's place after the Lions and England captain broke his hand when Leicester beat Northampton on Saturday.

Corry, Lewis Moody, Joe Worsley and Alex Sanderson head the list of Dallaglio alternatives, yet Corry has been suffering from hamstring trouble and his condition will require monitoring by England's medical team.

Woodward intends announcing his starting line-up on Tuesday morning, but he has already confirmed that Northampton scrum-half Matt Dawson will captain the side.

It completes a remarkable change in fortunes for Dawson, who was criticised for his comments ahead of the first Lions Test with Australia during the summer when he attacked coach Graham Henry.

However, he has won the backing of Woodward, and will hope for better fortune than the last time he skippered the national side, when they were beaten by Scotland at Murrayfield attempting to secure a Grand Slam, the same position they find themselves in this weekend.

Austin Healey's current form warrants selection, and it could be that he fills one of the wing slots, especially if Jason Robinson is preferred to Iain Balshaw and Matt Perry for full-back duties.

Healey and Robinson both seem certain to start, which puts huge pressure on Balshaw, who scored five Six Nations tries earlier this year, but lost form during the Lions tour to Australia and has not yet recovered it.

Robinson, in contrast, is flying and looks poised for a full England debut following three substitute appearances last term.

Healey could be handed the number nine jersey, such is his remarkable all-round ability, but it seems inconceivable that he won't make the starting XV.

"I am not on edge about the team selection for Ireland," Healey said. "I am proud to be in the squad.

"I have learnt over the years that you cannot expect anything with England because of the quality players we have.

"I expect a little more of myself than I am producing right now. I just seem to be going through games, and coming out the other end having done reasonably well.

"You should always want more in terms of your own form. If you are content with what you are doing, then you are probably not pushing yourself hard enough."