Ireland, France and England are locked in a three-way struggle for the title with the championship possibly to be decided by points difference if they win their final games.

Considerable ground needs to be made up by England in Cardiff, leaving the Stadio Flaminio and Stade de France as the crucial arenas with Les Bleus' points total just four higher than Ireland's.

Italy's victory over Wales - their second consecutive win in the RBS 6 Nations - ensured Ireland know it will be no simple matter to reel in the French.

Their cause has not been helped by the loss of inspirational Munster lock Paul O'Connell to a fractured thumb sustained in the 19-18 victory over Scotland.

Mick O'Driscoll is in pole position to replace his provincial team-mate in the starting line-up with Leinster's Trevor Hogan a leading contender to fill the vacancy on the bench.

Isaac Boss remains unavailable because of his shoulder injury but prop Marcus Horan could return when the team is announced at lunchtime on Tuesday.

Skipper Brian O'Driscoll fell awkwardly on the shoulder he had reconstructed and will be monitored closely while Gordon D'Arcy received treatment near the end at Murrayfield.

O'Sullivan said: 'The guys are physically and mentally tired. They were battle-weary at the end of the game against Scotland.

'The boys had to make some hard yards and several of them were pretty beaten up and battered.

'We are into the seventh week of the Six Nations and it's been like having a boxing match every week.

'The fellas are tired and the bumps and bruises don't go away easily.

'Now it's about managing people for Rome. You can't just keep beasting them every week, there is a balance between work and rest.

'We are getting into the endgame here.'

O'Sullivan is braced for a 'dogfight' against the Azzurri, who are guaranteed to avoid the wooden spoon following their controversial 23-20 triumph over Wales.

He added: 'Im not at all surprised Italy beat Wales. It is time people sat up and accepted that Italy are a serious team in the Six Nations now.

'Theyve won away from home this year and theyve won at home this year, and weve got our work cut out on Saturday, there's no doubt about that.

'Theyre on a roll now. Theyve got momentum after securing two wins on the bounce and were expecting a dogfight in Rome.'