Their return would probably mean there would be no place in the starting line-up for Gary Kelly and Steve Staunton, who both played in the final first-round match against Norway.
Charlton is waiting for Andy Townsend to return to training after damaging a hamstring. 'It is just a precaution that he missed the session,' Charlton said.
The Irish are aiming to meet Brazil in the quarter- finals, but Charlton said: 'Nobody should take anything for granted. Everyone expects them to beat the United States and Holland to beat us. But that might not be the case.
'We know the Dutch as well as anyone in Europe and they have to be respected because they still have very good players, even though they might have slipped a bit in the world ratings.
'We have about 13 or 14 players in our squad who can do it at this level, but it is not quite enough. We have to cover it with good organisation. With three or four more players we could match anybody.'
The Dutch coach, Dick Advocaat, has banned all talk of the heat in Orlando. He said: 'We will never get used to it, but talking too much only puts worry into the minds of the players.'Reuse content