Ireland's wheel of fortune
Gets the opportunity to nail down the outside centre slot for the championship and undoubtedly has the ability to do so. Carries exciting potential in attack, but it is essential his defence stands up to scrutiny as Wales will run hard down his channel.
Was the unluckiest member of Ireland's World Cup squad when his superb form in the run-in could not gain him first-team selection. The Ulster man goes into the Six Nations on a similar run of powerful performances with the capacity to be one of the tournament's most effective wingers.
Widely expected to lose out in the second-row to Donnacha Ryan, just as he has done for Munster this season, but O'Callaghan has been playing well and brings tremendous experience to the key front five area.
Has been going very well for Leinster and is handed another chance to lock down the out-half position after losing out to Ronan O'Gara at the World Cup.
A fantastic selection for the young Munster back-row. O'Mahony provides versatile cover off the bench and gains fitting reward for a season where he has oozed attitude and promise.
Given the way he has played for Leinster, McFadden must have fancied his prospects of getting Brian O'Driscoll's No 13 slot. Still has a key role to play as backline cover.
Has done nothing wrong and a great deal right since the World Cup in New Zealand, but must content himself with understudy duties again on a horses-for-courses basis.
Re-established himself as first-choice in New Zealand and has performed superbly for Munster this season. Now the battle starts over.
A constant in the World Cup and Six Nations squads, but O'Mahony's elevation to the match-22 is ominous for Leinster's warrior flanker.