Andrew Trimble during Ireland squad training this week

Ulster player Trimble edged out Geordan Murphy for the right wing spot in what O'Sullivan described as a "tough call".

Trimble hints that he was concerned that Ulster's mediocre recent form might stand against him.

"I'm fairly pleased that Eddie has kept faith with Rory Best and myself and given us another opportunity," he said.

The 22-year-old acknowledges that Ulster's recent struggles has had an effect on the province's Six Nations representation.

SIX NATIONS BLOG Cardiff proved a great fillip for the Irish in the 1990s when their form was up and down like Nigel Kennedy's elbow after Aston Villa had scored BBC Northern Ireland Sport's Jim Stokes More on our Six Nations blog

Neil Best appears to have been the main victim after losing out to Simon Easterby for a back-row starting spot at the Millennium Stadium while Bryan Young is left out of the match-day squad altogether after being involved in the autumn internationals.

"In the autumn internationals, we (Ulster) had a lot of representation. We were playing a lot of good rugby such as the first 40 or 45 minutes against Toulouse.

"The Irish selections reflected how well Ulster were playing at that time.

"Perhaps, it's gone a bit the other way now. There's been a few bad (Ulster) results in the last few games and we haven't been producing the performances we were looking for."

It will not be that much of a transitition going to the right wing Andrew Trimble

However while Trimble is undoubtedly under pressure to hold on to his starting place, he insists that he feels "more settled" in the Ireland squad for this his second Six Nations campaign.

"I know everybody a lot better. I can dander round the camp and chat to everybody and get on a lot better.

"It helps me to be myself a lot more and hopefully express myself on the pitch as well a bit better."

The Ulster player, who plays in his preferred centre position for his province, doesn't appear unduly fazed by switching from left wing to the right flank.

"It's one of the few benefits of not having that much experience on the left. It will not be that much of a transitition going to the right.

"It's going to be exactly the same - except on the other side, if that doesn't sound an obvious statement to make," adds Trimble with a giggle.

606 DEBATE: Who would you have selected?

With this modern Irish side playing with increasing width and variety, Trimble appears hopeful that he will see plenty of the ball in Cardiff.

"You can end up all over the place. To an extent, you have a free role to go about and pick the space and get involved where you can."