Six Nations 2015: Ian Keatley at 10, Sean O'Brien on flank

Sean O'Brien played for Ireland Wolfhounds against England Saxons last week

Munster fly-half Ian Keatley has been selected ahead of Ian Madigan for Ireland's opening Six Nations game against Italy in Rome on Saturday.

Keatley, 27, will form a half-back partnership with provincial team-mate Conor Murray as the Irish begin their defence of their title.

Johnny Sexton has been ruled out of the game as he ends a stand-down period because of a series of concussions.

Sean O'Brien starts at open-side with Jordi Murphy at number eight.

British and Irish Lions player O'Brien only made his comeback from a second shoulder reconstruction in 12 months when he played 50 minutes for Ireland Wolfhounds against England Saxons last Friday.

Head coach Joe Schmidt keeps faith in prop Mike Ross, even though the tight-head has lost his place at Leinster to Marty Moore in recent weeks.

Simon Zebo is selected on the left wing despite the return to fitness of Keith Earls, Luke Fitzgerald and Dave Kearney, who suffered a shoulder injury in Leinster's 20-20 Champions Cup draw with Wasps on 24 January.

Keatley has been capped three times by Ireland but has never featured in the Six Nations Championship.

He played against Canada and the United States on the 2009 summer tour and came off the bench in the 49-7 win against Georgia in November last year.

"Ian's combination with Conor Murray at Munster means they have a good understanding by playing together week by week," explained Schmidt.

"It's a vote of confidence in Ian - his percentages of kicking success have been strong since Christmas so I have confidence he will kick well.

"Ian Madigan gives us that flexibility off the bench, being able to slot straight into 12 or 10. It was a tight decision."

Jamie Heaslip misses out because of a shoulder problem that has limited his involvement in recent weeks, but he is expected to be available for the game against France in Dublin on 14 February, along with Cian Healy and Sexton.

"Jamie is a player you miss because of his experience but this will allow him to focus on the French game. He trained fully on Thursday, if he did so on Tuesday the decision may have been different," said Schmidt.

Leinster prop Healy hopes to have recovered from his long-term hamstring injury by then, while Racing Metro fly-half Sexton is expecting the all-clear on Thursday for the France game as he completes his enforced 12-week lay-off after a string of concussions.

Mike McCarthy is not included in the match-day squad after suffering a heavy concussion in the Wolfhounds' defeat by the Saxons.

Murray has made a full recovery from a neck injury in time to take his place in the line-up to face the Italians.

Bowe will make his first Six Nations appearance since 2012 while Ulster team-mate Payne makes his first-ever appearance in the competition, having played in the win over South Africa at the Aviva Stadium in November.

New Zealand-born fly-half Kelly Haimona will make his Six Nations debut for Italy in Saturday's game.

Haimona made three appearances for his adopted county in the autumn when he scored 35 points.

Coach Jacques Brunel makes two changes from the 22-6 defeat by South Africa in the autumn with George Biagi replacing injured lock Quintin Geldenhuys and Francesco Minto taking over from Samuela Vunisa in the back row.

TEAMS

Italy: A Masi; L Sarto, M Campagnaro, L Morisi, L McLean; K Haimona, E Gori; M Aguero, L Ghiraldini, M Castrogiovanni; J Fumo, G Biagi; A Zanni, F Minto, S Parisse (capt).

Replacements: A Manici, A de Marchi, D Chistolini, M Fuser, M Barbini, G Palazzani, T Allan, G Venditt

Ireland: R Kearney; T Bowe, J Payne, R Henshaw, S Zebo; I Keatley, C Murray; J McGrath, R Best, M Ross; D Toner, P O'Connell (capt); P O'Mahony, S O'Brien, J Murphy.

Replacements: S Cronin, J Cronin, M Moore, I Henderson, T O'Donnell, I Boss, I Madigan, F Jones.