Paddy Wallace has been in good form for Ulster this season

Wallace, who can play in the centre or at fly-half, earns his call-up after impressing for Ulster this season.

His Ulster team-mates Bryan Young and Issac Boss are also in the 22-man squad along with Munster's Frankie Sheahan, who returns after a neck injury.

Brian O'Driscoll and Andrew Trimble are minor injury worries for the Irish.

Irish skipper O'Driscoll suffered an ankle injury in training while Ulster winger Trimble has a hamstring problem.

There is no place for Ulster prop and captain Simon Best despite his recovery from a broken leg.

Boss was given the nod ahead of Eoin Reddan to supply back-up to first choice scrum-half Peter Stringer.

All of Ireland's Triple Crown-winning line-up feature in the 22, except for Munster hooker Jerry Flannery who is out until Christmas with a shoulder injury.

"I'm keeping one eye on the World Cup and am considering a bit more depth in the squad, certainly in some positions," said O'Sullivan.

"There are new faces and I would like to use the three games to get more people on the pitch.

"Having said that, I'm not going out with the attitude that it's an experiment - it's not.

"We want to win the three Test matches, but we have more elbow room.

"The first game against South Africa will tell us a lot about how we are and hopefully we'll have more room for manoeuvring over the course of the three games."

O'Sullivan will name his starting line-up to face South Africa next Tuesday.

Ireland squad:

Forwards: Neil Best, Rory Best, Simon Easterby, John Hayes, Marcus Horan, Denis Leamy, Donncha O'Callaghan, Paul O'Connell, Malcolm O'Kelly, Frankie Sheahan, David Wallace, Bryan Young.

Backs: Issac Boss, Girvan Dempsey, Gordon D'Arcy, Shane Horgan, Geordan Murphy, Brian O'Driscoll, Ronan O'Gara, Peter Stringer, Andrew Trimble, Paddy Wallace.