Johnson has confidence in Corbisiero to thrive in his baptism of fire

(David Ashdown)

England thought they knew precisely where they stood in relation to this year's Six Nations Championship following their precious opening-round victory in Wales eight days ago.

Suddenly, they find themselves thinking again. The withdrawal of their Lions prop Andrew Sheridan from this afternoon's meeting with the strong-scrummaging Italians at Twickenham means Alex Corbisiero of London Irish will make his debut at loose head against no less a figure than the fearsome Martin Castrogiovanni. It should be quite a meeting of minds.

Born in New York, the newcomer has Italian ancestry: his grandfather Riccardo left the tough southern city of Naples for the Big Apple in the 1950s. The Argentine-born Castrogiovanni, widely acknowledged as a godfather of the set-piece, also has links to a part of Italy where the words "respect" and "honour", long part of the front-rower's vocabulary, take on a slightly darker hue. His folks hail from Sicily. "Real mafia country," as he once said.

Sheridan, by some distance the most experienced of England's current tight-forward unit, injured his lower back during a training session on Thursday and pulled out of the side yesterday morning. Corbisiero, initially selected by his club for today's Premiership fixture with Newcastle at the Madejski Stadium, was promoted ahead of the Bath prop David Wilson, who remains on the bench. Wilson filled in at loose head towards the end of last Friday's contest at the Millennium Stadium, but is a tight-head specialist by instinct and breeding.

At 22, Corbisiero finds himself a part of one of the youngest England front rows in history. The hooker Dylan Hartley is 24, a year older than the starting tight-head Dan Cole. The Azzurri combination are much older, and far more knowing in the ways of international rugby. Between them, Castrogiovanni, Leonardo Ghiraldini and Salvatore Perugini have 181 caps. Their opponents can muster only 36 between them.

This might not count for a great deal in the usual run of things, but with Italy attaching such importance to their set-piece game, any English weakness in this area will be cruelly exposed. Martin Johnson, the red-rose manager, knows this to be the case: yesterday, he admitted that during his own playing days, he rarely experienced anything other than a "bloody hard game" against Italy. Yet he did not think twice about pushing Corbisiero into the fires.

"He's very humble, very switched on," Johnson remarked. "He's always impressed me when he's been in the group, and has done himself the world of good recently. On Tuesday, after a hard session in which the forwards really went at each other, he said: 'Thanks for having me in.' I told him to remember he was one injury away from playing, which is how it turned out. We found a Test-quality performer in Tom Wood down in Wales, and I'm hoping we've found another one here. Tom is a solid character, Alex is a solid character. That's what we need. Without character, you can't play the game at this level."

Corbisiero has had his injury issues, but his contribution to the London Irish cause in recent months has been well-nigh faultless. The Exiles suffered 10 consecutive defeats across three competitions either side of Christmas, yet Corbisiero's standards never dropped. Toby Booth, the head coach, credited him with "re-energising" the team.

Despite the late change at the sharp end, England remain hot favourites to maintain their unbeaten record against the Italians. Corbisiero may be as green as grass, but he is at least familiar with the threat posed by the Leicester-based Castrogiovanni, having confronted him more than once in Premiership rugby. Unless they fall apart completely at the set-piece, the home side should win more than enough ball to bring their free-running back three into the game.

But they must think on their feet and adapt to circumstances as they unfold, rather than stick blindly to the process that worked for them in Wales. As Mike Tindall, the captain, agreed yesterday, Italy will bring a very different approach to business. "When you play Wales, you know they'll keep the ball on the field in an effort to set a high tempo," the Gloucester centre said. "The Italians are far more interested in a set-piece contest, in slowing things down. This is where our learning curve comes in. We have to keep our game balanced, to be flexible."

Last autumn, England failed the flexibility test. Having wowed Twickenham by beating the Wallabies in an exhilarating runaround, they tried to play the same way against a Samoan side who weren't much interested in running anywhere, unless it was tight to the tackle area, and were made to work hard for their victory. Seven days later, they were smashed by the Springboks.

South African levels of physicality are beyond the scope of this Italian team, but the Azzurri will do their best to match them all the same. They have no choice, given the pedestrian nature of their back division. Corbisiero, unusually mobile for an 18-stoner, is unlikely to be run off his feet. He will, however, do well to avoid being knocked off them.