Then there's the case of David Humphreys. As speculation and whispers regarding the make-up of Ireland's World Cup squad did the rounds over the past few weeks, there was little or no mention of the Ulster outhalf but don't think for one second that he's been forgotten by O'Sullivan. His name may not be listed among the coach's official pool of back-up players for the tournament but that doesn't necessarily mean he won't be there at some point.

But what about the outhalf 's retirement from international rugby, something that, you'd imagine, might represent a fairly substantial road-block to his appearance in France at some point over the coming months? True, Humphreys did confirm back in March 2006 (he actually made his decision a month earlier before being apparently brow-beaten into proclaiming that he still hadn't made up his mind) that he wasn't available to play for Ireland any longer but he didn't exactly seal the doors shut on his way out of camp, if O'Sullivan is to be believed.

"I was hoping he would stay on but I understood why he left, " the Irish coach told The Irish Times in May of last year. "But he did say to me when he was stepping down, 'Look, if you are stuck at any point I would consider the possibility of coming back.

I'm playing for Ulster and if you think I'm playing well enough and you need me, I'd be happy to help out.' It could happen. I'm not ruling it out.

Let's see what happens."

Any observer who's watched what's happened since could only draw the conclusion that either O'Sullivan thinks Ronan O'Gara is immune from injury, or that he knows Humphreys will dig him out of a hole should the Munster out-half pick up an injury during the World Cup.

The reason we say this is because the coach has invested hardly any time or effort in nurturing a back-up to O'Gara. Paddy Wallace started at ten against Scotland at Murrayfield last weekend and while his running game caught the eye at times, he never really dominated the game like all good out-halves do.

The truth is that Wallace has yet to play a game of any consequence for Ireland and the corollary of all this is that the Ulster player, and indeed Ireland, would be seriously behind the eight ball, as the coach himself might say, if he had to start against Argentina, France or the All Blacks in the absence of an injured O'Gara. As for Jeremy Staunton, who sits just below Wallace in the reserve outhalf pecking order, he's hardly been given a game of either the consequential or inconsequential type over the past 18 months. He's well undercooked also.

Taking all that into consideration, you can only hope that Humphreys would be prepared to answer Ireland, and O'Sullivan's, call should . . . and let's keep our fingers and toes crossed that it doesn't happen . . . O'Gara pick up a knock before or during the World Cup. Injured players can be replaced at any point during the tournament, the only condition being that they are removed from the World Cup squad completely and can't return should their injury clear up. At present, Humphreys is in preseason training for his final year with Ulster and there's no question he'd be physically ready to play at the World Cup if called upon.

Which just leaves the matter of whether the player would be willing to come out of international retirement.

There are a couple of things to consider here. First, it's important to remember why Humphreys retired from international rugby. He wasn't disenchanted with the game, or annoyed that he was playing second fiddle to O'Gara, but fed-up with having to spend so much time in Irish camp away from his wife and three young children. A three or four week stint in France might prove just about acceptable.

The second thing to consider is the integrity of the man himself. Humphreys has always been a dedicated professional, a loyal and gutsy player and we don't doubt for one second that he'd agree to help his country out should they find themselves in trouble in France.

Finally, there's the not insignificant matter of who pays the player's wages. If it came to it, we have no doubt that the IRFU would remind Humphreys where his monthly pay cheque comes from, but we doubt that things would ever have to go that far.

So here's our call on the issue. If Paddy Wallace is ruled out of the tournament, Jeremy Staunton will fly in from London to replace him but if O'Gara, God forbid, falls, Humphreys will come back on board. And you thought last Sunday's squad announcement was the end of the selection debate.

It's only the beginning.