Seán Moran talks to Ciarán O'Sullivan about his conversion from attacking wing back to full back, a move successfully made by Kerry's Seamus Moynihan

It will be a bit of a shock to see Ciarán O'Sullivan lining out as selected in tomorrow's Bank of Ireland Munster football championship semi-final against Kerry. Since he hit the deck running in his first championship season nine years ago, O'Sullivan has always been associated with mobility, athleticism and creativity.

Although a wing back, his well-judged attacks and intelligent kicking created a platform for the forwards. It was no surprise to see him shuffled around the pitch to centrefield and into the half forwards. But full back?

When he first took up the position this spring it was assumed to be one of those league experiments, which frequently appear to be either born of desperation on a given weekend or for the private amusement of the manager. Larry Tompkins, however, obviously had something in mind.

"I played there before with Beara," says O'Sullivan, "but probably not for eight or 10 years. I was told on the Tuesday or Thursday before the game. I was a bit taken aback but it wasn't a major problem. There were two good corner backs beside me."

It was early March in Tuam and the All-Ireland champions Galway provided the opposition. Playing on Kieran Comer, Cork's new full back did well and sent his man packing to the bench, scoreless with three quarters of an hour played.

There is one staggeringly successful precedent for the switch. Tomorrow his opposite number will be Seamus Moynihan who transferred to the position with a similar career history and in the space of a season was Footballer of the Year. Not getting ahead of himself, O'Sullivan has found the transition manageable.

"It's totally different to wing back. I find it a change, a challenge. You're the last line of defence. On the wing you've an opportunity to go forward. If you slip up, there's always someone behind covering for you. At full back there's no second chance. You mightn't be involved for five minutes and suddenly there's a ball in. Concentration's important.

"Since I've been playing there, I've never been standing beside a full forward. The days of Bomber Liston are gone. With modern full forwards you mightn't be standing on the edge of the square all day, just moving all the time. A lot of teams move a corner forward out and play two inside so that you mightn't ever be in the full-back position at all.

"I found most of the guys I marked a handful at times but Brendan Devenney of Donegal was very lively, the sort of player who won't stay on the full-forward line at all let alone on the edge of the square. Johnny Crowley is the same. He's more a forward than just a full forward. He can score from anywhere."

Thirty two this year, O'Sullivan's life has changed in the past couple of years. He has moved from the city back to the Beara Peninsula, taking his young family and establishing his own business.

"I started my own oil distribution service with my wife Geraldine. She's been outstanding. She takes care of the office side of the business, does the books and looks after everything. If it wasn't for her I wouldn't be able to play football for Cork.

"In fairness to Larry (Tompkins) he made it easy on me over the winter. I was allowed train with Bantry and only had to go to Cork once a week. I couldn't have done it otherwise because that's my busy time of the year."

But as the season took off and preparations intensified, the demands on his time have grown. Delighted to be home and enjoying what he and Geraldine, who is also from west Cork, Adrigole, feel is a better quality of life, O'Sullivan has a daunting schedule to keep his inter-county career alive.

"When I lived in Cork it used often take me only 12 minutes to get to training. Now the round trip takes over six hours. I leave at about 4.30 p.m. and don't get home until 11 p.m. For all the knocks and disappointments, the hardest thing by far about playing is training.

"I won't come the poor mouth with you but there are times when it's hard. The weekend we went to Donegal I left at 11 a.m. on a Saturday morning and wasn't back until around 2 a.m. on Monday morning. I'm lucky that local people understand but it puts me under pressure. I could work longer hours if I didn't have to get into the car.

"I can make up some of it but you can also lose business by not being around. I drive the truck myself and don't have a relief driver because the we're only just set up and couldn't afford that. I could be on the way to Cork when someone rings up looking for a delivery and I have to say no and let the business go."

Tomorrow is the start of another championship and Munster's main event is up first for Cork. His county locked in perennial combat with Kerry, O'Sullivan can itemise the frustrations of each setback in the less successful, recent past (Cork have won only one of the last five meetings).

"Last year we felt very hard done by ... Decisions were constantly going against us. I'm not saying that's why we lost but it's very annoying. But you can't say 'to hell with it'. You've got to keep going."

And he does.