RUGBY Six Nations Championship: One steps out, another steps back in again. As Eddie O'Sullivan is wont to say, you have to dance with the ladies at the ball although of late even a tango, never mind a twist, might carry the risk of tripping over each other's shoelaces for Ireland's jinxed centres.

The Irish midfield is deemed to be a prime source of strength, which is just as well given the latest setback which has sidelined Gordon D'Arcy in addition to Shane Horgan and has obliged O'Sullivan to perm his fourth different centre combination in four games.

After the first-choice pairing of Brian O'Driscoll and D'Arcy took the field in Rome - Ireland's "dream" back line lasting barely 25 minutes in harness - that hamstrung pair were replaced by a Kevin Maggs-Horgan axis in Murrayfield, followed by the Horgan-O'Driscoll combination against England.The enforced changes cannot help Ireland's attacking fluidity although it is of immense comfort to have someone of Maggs' experience - he is Ireland's most capped centre and third most capped player of all time with 67 Tests behind him.

"I got my first cap with Maggsy," recalled O'Driscoll yesterday of his debut in Brisbane against Australia in the summer of 1999. "I couldn't tell you how many times we've played together but it must be in the region of 30 or 35 times. After training this week I don't see any problems in picking up where we left off.

O'Sullivan had admitted that they were reasonably confident after D'Arcy's comeback on Sunday that last season's player of the championship would be fit to return to the starting line-up. "But he felt he hadn't as much power as he wanted, that he wasn't able to fire on all cylinders. He still had a bit of discomfort so we took him for a scan yesterday (Monday) and it revealed some residual scarring that hadn't cleared up.

"He's 95 per cent of the way there but the last five per cent seems to be taking a lot longer," commented O'Sullivan.

When D'Arcy might now be considered fully fit is akin to asking how long is a piece of rope and O'Sullivan admitted: "I'd be worried about the Wales match to be honest."

Amid the gnashing of teeth over D'Arcy's desperate misfortune, which must even cast a cloud over his Lions' hopes, the loss of Horgan's physical strength could be just as keenly felt, although Maggs will bring plenty of midfield steel. Which is just as well, given the selection of Ludovic Valbon looks a clear statement of intent by France coach Bernard Laporte to continue with the preference for hard, straight-running centres to set up midfield targets or check the drift defence.

Asked whether Ireland can expect to face the French team who threatened to blitz Wales off the park in the first-half or the one which just as suddenly lost its bearings in the second, O'Sullivan said: "I've no doubt about it - the first half against Wales. We would be stupid to expect anything else. They're not exactly short of pace and they're a very intelligent side, and it's not like they're going to make the same mistakes again."

O'Sullivan also earmarked an ability to be more precise in Ireland's use of the ball and force France to do more defending than had been the case against England, highlighting the breakdown and the scrum as areas which will require strong refereeing from Tony Spreadbury.

O'Sullivan was not inclined to discuss the vexed possibility of further mishap to his midfield on Saturday beyond saying "it would depend how the game is going" and perhaps how long was gone. The options aren't plentiful, given it would probably mean an introduction for Harlequins' twice-capped former Connachtman Gavin Duffy.

Duffy has played a fair amount at centre, though at Harlequins has been exclusively employed as a fullback. An alternative scenario would be to move Murphy from fullback in to outside centre, where he has played once before in a World Cup warm-up match in Perth almost two years ago.

The starting line-up has 694 caps to their name, while the squad of 22 boasts 896 Tests between them. Hardly a Six Nations game in the last two seasons goes by without another player reaching the 50-cap landmark, and Denis Hickie reaches that milestone on Saturday.

A notable addition to the squad's numbers this week has been Clive Woodward, the Lions' head coach having joined the Irish camp yesterday for the week ahead to watch and observe the players at work, as he has been doing with each of the home unions in the weeks they've been playing the French. He will adopt a watching brief as well as endeavouring to have discussions with players individually.

15 Geordan Murphy (Leicester)

14 Girvan Dempsey (Leinster)

13 Brian O'Driscoll (Leinster, capt)

12 Kevin Maggs (Ulster)

11 Denis Hickie (Leinster)

10 Ronan O'Gara (Munster)

9 Peter Stringer (Munster)

1 Reggie Corrigan (Leinster)

2 Shane Byrne (Leinster)

3 John Hayes (Munster)

4 Malcolm O'Kelly (Leinster)

5 Paul O'Connell (Munster)

6 Simon Easterby (Llanelli)

7 Johnny O'Connor (Wasps)

8 Anthony Foley (Munster)

Replacements: 16-Frank Sheahan (Munster), 17-Marcus Horan (Munster), 18-Donncha O'Callaghan (Munster), 19-Eric Miller (Leinster), 20-Guy Easterby (Leinster), 21-David Humphreys (Ulster), 22-Gavin Duffy (Harlequins).