DECISIONS, decisions, decisions. It seems to be one dilemma after another for Mick McCarthy these days. Just as the choice about who to play up front is made for him by the injuries to Niall Quinn and Keith O'Neill, back comes Roy Keane and suddenly the Irish boss is agonising over what to do with him.

The attraction of playing someone of Keane's abilities in the centre of the defence is obvious. He's an outstanding footballer and he has plenty of experience in the role, having fulfilled it many times during his days at Nottingham Forest.

On those occasions he made it abundantly clear that he has all the tools required for the position. England, with Glenn Hoddle making a concerted effort to get his central defenders to come forward and lend a hand in midfield, would cry out to have Keane available to them in exactly that role.

His fierce competitiveness, his ability to win possession and the ease with which he carries the ball forward and lays it off to those around him make him a natural choice to slot into a team as a sweeper in a three man defence.

For all that, however, defence is not Keane's best position, and it's a little hard to understand why McCarthy would be attracted to the option of deploying him there when he could be sent into his more natural role in the centre of the field.

At this sort of level, it is in the midfield that games are won, and many of the same qualities that would make the Corkman a fine central defender ensure that he is a superb midfielder. His talents in this area give his team a considerable head start in the battle to gain the upper hand around midfield, and, against a side like Iceland, the sooner we can demonstrate that superiority the sooner we will kill off any faint hopes the visitors might harbour of pulling off a bit of a shock tomorrow afternoon.

Ideally, Keane would complete a midfield that also included Ray Houghton and Andy Townsend, with Jason McAteer switching to the right back position and Alan McLoughlin having to settle, as he so often has to, for a seat on the bench.

Against the Macedonians, Townsend, McAteer and McLoughlin did particularly well, and the Portsmouth player, who has been such a loyal servant to the Irish team over the years, was probably our best player on the night.

Not wanting to make changes to a section of the team on the basis that it has done well in a single match is not however a good enough reason for deciding against playing your best player in his best position.

Admittedly, it seems likely that the Icelandic team should be straightforward enough to deal with. But we have to ask whether there would be talk of playing Keane in defence if it were Romania we were going out to face; it's fairly obvious that the answer is no.

On the face of it, Keane's replacement of McLoughlin would be the most simple way to proceed for McCarthy. But a little more tinkering would be preferable. Jeff Kenna played well last month, but against an Icelandic side that will be missing several key players we would be better served by employing McAteer down the right, where he would be likely to get in behind defenders and cause more problems than the Blackburn player tends to do.

On the other side, it would be nice to see Ian Harte left where he is. It takes about 10 or 12 matches to really get established in a team at international level, and the more of these sort of games, against the weaker teams in the group, that a player like Harte can get under his belt then the more at ease he will be towards the end of the qualifying process when the pressure on the side may be starting to mount.

That leaves you with Denis Irwin to play with the back and it is to Keane's Manchester United team mate that it would hand the pivotal defensive role, with Gary Breen and Phil Babb playing either side of him.

Like Keane, Irwin is very adaptable. He has played in a number of positions already and has long since proven that his talent is easily sufficient to allow him to cope with whatever task is assigned to him. He is an excellent player of the ball, wonderfully dependable and excellent on either foot. The job seems made for him.

For Babb, this match could be a marvellous opportunity. From a time, not so long ago, when his career seemed to be going from strength to strength at club and international levels, he has ceased to be an automatic choice - or anything like it - for Mick McCarthy, while his recent form at Liverpool has been as disappointing as that of his fellow defenders.

Against Iceland, though, he is likely to be handed the chance to re establish his credentials against poor opposition. Steve Staunton did very well last time out, but Babb has it within his power to make it difficult for the manager to bring the Villa player back in when he is fit again. It will be interesting to see how well he rises to the challenge.

Up front, meanwhile, we're back to the old reliables. Neither John Aldridge nor Tony Cascarino has anything left to prove, but both seem as keen as ever to seize the opportunity that the current injury situation has offered them.

Cascarino, particularly in the light of his two goals last time out, is a certainty to start. But for Aldridge a lot will depend on just how long the manager feels that he can reasonably expect the 38 year old to keep running.

If it were up to me, I would stick Aldridge out there at the start but make it clear to him that he was to restrict his movements to the width of the 18 yard box. If he did that for 70 minutes or so, before being replaced, then he could still cause the Icelandic defenders considerable problems, because he is still the best finisher available.

If, on the other hand, David Kelly is preferred it will presumably mean only that Aldridge's contribution will be, at the end, rather than the start of the game which, in its own way, may be of benefit to the Tranmere player.

Whoever plays up front, though, should manage to produce a few goals, because if we don't beat a depleted Iceland side on home soil, then, when the time comes to start travelling again in the new year, we are going to have considerable problems scrapping our way out of this group.