O'Connell pulled out of his side's victory over Scotland at the 11th hour last weekend - much to the amusement of some of his battle-hardened colleagues - but after a course of antibiotics the Ireland second row will again have its usual Munster presence.
Warburton meanwhile, was deemed fit enough for a place on the bench in Wales' opening victory, having recovered from a shoulder injury, but he takes his place at openside flanker in Dublin.
Wales and Warburton are only too aware they will need to improve on last week's performance when they face the only side that beat them in last year's RBS 6 Nations.
They're defending an unbeaten away run in the Championship that dates back to 2011 and they're in pursuit of an historic third straight RBS 6 Nations crown - but Warburton is under no illusions as to the task ahead.
"It was good to get a hit-out just to get the lungs going again, just to feel getting back up off the floor and working hard. You try to replicate that in training.
"It always takes a game to get that timing back, that's why it was good to compete at the breakdown last weekend and get some timing going. It was good to get rid of the cobwebs."
The recent clashes between to two sides have been riveting affairs. Last year Ireland triumphed in Cardiff, the year before Wales won in Dublin while before that, it was Warren Gatland's side who got the better of the Men in Green in their World Cup quarter-final clash.
"There is no team we fear, and it's great to go away from home and have that confidence that you can win, and even sometimes you have to grind out the ugly win - that's very important, too," said Gatland.
"I think if you look back at the last World Cup, we were absolutely outstanding (against Ireland in the quarter-final).
"We put in a superb display that day, but Saturday is going to be tough."
As Lions coach, Gatland will be familiar with a number of his side's opponents on Saturday and while he can welcome back Warburton, as well as loosehead prop Gethin Jenkins, he has resisted the temptation to call on Jonathan Davies, who came through 40 minutes unscathed for the Scarlets last week.
It means there will be no mouth-watering clash at outside centre between Davies and Brian O'Driscoll but another intriguing sub-plot is that of the two Kiwi coaches with Joe Schmidt leading Ireland in his maiden RBS 6 Nations.
As well as welcoming back O'Connell, he also has Gordon D'Arcy returning at inside centre but Schmidt is keeping his cards close to his chest ahead of his showdown with Gatland.
"Man for man they are a very big side and we are going to have to be fairly smart about the way we play," he said.
"There are one or two things we will try to implement on Saturday but we'll have to assess post-match whether they have worked or not.
"We have a six-day turnaround so we trained for an hour on Tuesday, for an hour on Thursday, and we have the captain's run on Friday.
"The first three days after the Scotland match were largely used for recovery as the match was played at a reasonably high tempo, so we've just been keeping a lid on things training-wise."