Ronan O'Gara at stand-off as Ireland open defence

IRELAND will open their Grand Slam defence with Ronan O'Gara at fly-half after Jonathan Sexton was ruled out against Italy with a leg injury.

Sexton seized the No10 jersey last autumn when outstanding performances against Fiji and South Africa thrust him above O'Gara in the pecking order. Both players have been in fine form but 24-year-old Sexton, capped twice, was favourite to start at Croke Park on Saturday – until a dead leg injury ended his involvement.

Paddy Wallace, who played at fly-half in the A team defeat by England Saxons on Sunday, provides cover on the bench. Leinster back row Kevin McLaughlin will make his debut at blindside flanker after Stephen Ferris lost his battle with a knee injury.

Andrew Trimble makes his first international appearance since March 2008 with his fine season for Ulster nudging him ahead of Keith Earls on the left wing.

Gordon D'Arcy, another Ireland back who is enjoying an eye-catching season, features at inside centre – a position held by Wallace in the autumn. Munster front row Jerry Flannery is given the nod at hooker, despite having played no provincial rugby since recovering from the Achilles injury that has kept him out for the past two months.

Rory Best of Ulster, who also started for Ireland A in Bath last weekend, is included on the bench to continue his comeback from neck surgery. Brian O'Driscoll and Donncha O'Callaghan sat out training on Monday with minor knocks but both make the starting line-up. In total there are four changes to the side that toppled world champions South Africa 15-10 in last autumn's dripping climax at Croke Park. Ireland start the Six Nations second favourites behind France while Italy, who are without injured talisman Sergio Parisse, are odds-on to land the wooden spoon.

Meanwhile, Italy head coach Nick Mallett has named his 24-man squad for the game. Bayonne fly-half Craig Gower has been included in the squad but is doubtful for this weekend's match as he is struggling with a knock to his left knee, which means uncapped Rovigo stand-off Riccardo Bocchino could make his Azzurri debut in Dublin.

Antonio Pavanello, Simone Favaro, Manoa Vosawai, Andrea Marcato, Matteo Pratichetti and Michele Sepe have joined Italy's A team for Sunday's match against England Saxons in Treviso.

Ireland team: R Kearney (Leinster); T Bowe (Ospreys), B O'Driscoll (Leinster capt), G D'Arcy (Leinster), A Trimble (Ulster); R O'Gara (Munster), T O'Leary (Munster); C Healy (Leinster), J Flannery (Munster), J Hayes (Munster); D O'Callaghan (Munster), P O'Connell (Munster), K McLaughlin (Leinster), D Wallace (Munster), J Heaslip (Leinster). Replacements: R Best (Ulster), T Court (Ulster), L Cullen (Leinster), S O'Brien (Leinster), E Reddan (Leinster), P Wallace (Ulster), K Earls (Munster).

SIX NATIONS TEAM GUIDES:

Scotland

England

France

Ireland

Italy

Wales