Ulster centre Luke Marshall has been chosen to partner Brian O'Driscoll in Ireland's Six Nations opener against Scotland on Sunday, ahead of stomach bug victim Gordon D'Arcy.
Head coach Joe Schmidt has propelled 22-year-old, four-cap Marshall into his starting line-up, despite 75-cap D'Arcy's impressive performance in the 24-22 November defeat to New Zealand.
Former New Zealand schoolteacher Schmidt, in his maiden Six Nations Championship in charge of the Irish, felt Marshall was a better option after illness disrupted D'Arcy's training schedule.
"Gordon's stomach bug was the sole selection criteria, really," Schmidt said. "Luke Marshall has played really well in the Heineken Cup in big games.
"He played in the Six Nations last year and played very well against Scotland.
"I thought he played well against Australia in the autumn too. He made a defensive error at one stage, but he's learning all the time. He's working hard at everything we're trying to do.
"He's between Johnny Sexton and Brian O'Driscoll, so experience-wise, he's a bit inexperienced but either side of him he has two players who can help him navigate his way through the game."
Marshall's promotion is a reward for fine club form as his province blasted through to the Heineken Cup quarter-finals with a flawless six wins in pool stage action.
Former Ireland and British Lions skipper O'Driscoll will win his 129th cap, breaking Ronan O'Gara's all-time record.
Ireland host the Scots at the Aviva before taking on Wales in Dublin just six days later, and Schmidt's initial midfield selection may well have a strategic element to it.
The Kiwi can reasonably be expected to unleash his former Leinster underling D'Arcy on the Welsh in round two, after previously admitting the short turnaround between the two fixtures would need careful negotiation.
Marshall will operate as a second playmaker alongside fly-half Johnny Sexton, with Schmidt intent on adding width to Ireland's attack.
Ulster wing Andrew Trimble starts ahead of Fergus McFadden, winning his first cap since last summer, while Dave Kearney wins his first Six Nations start, alongside older brother and full-back Rob.
Luke Fitzgerald was likely to start but picked up an injury in midweek, with Tommy Bowe and Keith Earls being longer-term casualties.
Chris Henry slots into the back-row for Sean O'Brien as expected, with the Leinster openside out for four months following shoulder surgery.
Lock Dan Tuohy has been given the nod over Iain Henderson on the bench, and Paddy Jackson has been preferred to Ian Madigan as replacement cover for fly-half Sexton.
Emerging Leinster prop Martin Moore will make his Ireland debut on Sunday after winning a slot on the bench.
The 22-year-old tighthead prop has been named as a replacement for the Scotland clash and will join the fray for the final quarter when Schmidt empties his bench.
Moore and Leinster team-mate Jack McGrath have impressed senior front-rowers in Ireland training this week, notably in scrummaging sessions.
Both will be tasked with adding impetus in the closing stages on Sunday, with Schmidt underlining his high regard for the fast-developing Leinster duo.
Ireland: R Kearney, D Kearney, O'Driscoll, Marshall, Trimble, Sexton, Murray, Healy, Best, Ross, Toner, O'Connell (capt), O'Mahony, Henry, Heaslip
Replacements: Cronin, McGrath, Moore, Tuohy, O'Donnell, Boss, Jackson, McFadden