The Munster second-row has not played for his country since picking up an injury against Scotland in last season's RBS 6Nations.
But he will pull on the green of Ireland once again when they take on Italy in their Six Nations opener. O'Connell has emphasised the importance of starting with a bang believing this year's Championship is one of the most open to date.
"There's no standout team that looks like they are going to run away with it," said O'Connell.
"It's a tournament that's all about momentum. You have to get off to a good start and anything can happen from there.
"In 2009, we came into it with confidence low after a poor Autumn and poor Six Nations in 2008. We got off to a good start and found a bit of momentum. The team that can do that is the team that will win it.
O'Connell has benefited from two hard-fought games following his return from injury and suspension and is confident he is nearing a return to his best.
"Rugby, more than any other sport, is very hard to train for, added O'Connell. "The contrast of mauling, tackling, wrestling on the ground for the ball, going into sprinting, to jogging, to jumping, to ball carrying is a very hard dynamic to replicate in training.
"It is when you come to matches that the work you have done begins to come through. It always takes three to four games for that to happen.
"The way the game is going, it is more and more physical. There is always going to be injuries. The teams that can manage that are the teams that are going to be successful."
Former Lions Tommy Bowe, Rob Kearney, Geordan Murphy, Shane Horgan, Jamie Heaslip and Stephen Ferris are all out of action.
But Kidney was still able to call upon Luke Fitzgerald, Brian O'Driscoll, Gordon D'Arcy and Keith Earls in the backs while Donncha O'Callaghan, Paul O'Connell and David Wallace line-up in the pack. There is also a place among the replacements for Ronan O'Gara.
And while the Lions skipper expects a tough opener at the Stadio Flaminio, against a powerful Italian out-fit, O'Connell reckons Ireland are better prepared for injuries than ever before.
"Italy have an excellent pack. They take you on up front, maul 50 per cent of their ball and they have a strong scrum. It's always a tough physical game for us, it's never an easy one.
"We are further down the track in terms of being a squad than we were two years ago. Injuries are never a good thing for the squad. I reckon it largely, won't hurt the team. This goes to show what a position of strength we are in."
O'Connell is one of eight Lions tourists named in Declan Kidney's match-day squad despite the injury blows.