Kevin Kilbane is the Republic of Ireland’s only serious injury worry as they continue their preparations to face Saudi Arabia on Tuesday.
The midfielder is believed to be struggling with a knee problem sustained during this morning’s training session in Chiba but the coach is confident Kilbane will be fit in time for their final Group E clash.
McCarthy, meanwhile, has stressed the need for his squad to ignore the favourites tag and concentrate on playing their own game against the Saudis.
Ireland can assure themselves of a place in the next round if they defeat Saudi Arabia by a two-goal margin.
But McCarthy wants to head off any possibility of his side becoming burdened by their status as favourites.
"Too often teams have gone from performing well as underdogs to playing like absolute amateurs when put in the position of favourites," McCarthy said.
"It's almost as big a test of mental strength. If the goals don't come the important thing is not to panic and just retain the self-belief.
"Fortunately, we have that in spades at the moment," he added.
Though Saudi Arabia are already out of the tournament, McCarthy believes they will have a point to prove.
"They are not going to be a walkover if they repeat their performance against Cameroon. They showed great spirit and skill going forward," he said.
The Saudis have injury concerns of their own as they attempt to salvage something from an uninspiring World Cup campaign with both skipper Sami Al-Jaber and leading striker Obeid Al-Dossary ruled out.
Al-Jaber, due to retire after the tournament, had to undergo an appendix operation in Japan while Al-Dossary has to undergo an operation on ligaments in his left knee which he injured in the first-half of the 1-0 defeat by Cameroon last Thursday.