Furious Everton manager Ronald Koeman has claimed that Martin O'Neill and James McCarthy ignored medical advice to try and find a role for the player in last Friday's World Cup qualifier with Wales.
oeman has alleged that both the Everton and Irish medical teams had reservations about fielding the midfielder in the crucial Aviva Stadium encounter due to his ongoing hamstring problems.
McCarthy was named in O'Neill's starting XI but was pulled out of the match shortly before kick-off. The Irish boss said that the Glaswegian 'overstretched' in the warm-up.
He is now set for another spell on the sidelines and Koeman - who clashed with O'Neill in the autumn over the use of the player - is furious.
"It was a final decision against the medical staff of Ireland and also against the medical staff of Everton," said the Dutchman.
"And there are two people responsible for that. One is the player by himself. Finally, if he says, yes I'm fit, ok, but even the player needs protection from the manager and, once again, they didn't give that protection to the player."
Koeman contrasted that situation with his predecessor Roberto Martinez's treatment of his Everton contingent with Romelu Lukaku spared from full involvement in a friendly with Russia because he came through a tough qualifier with Greece. "You like people to understand - not like Ireland," he said.
Read more: 'He is one of the best professionals I’ve ever worked with' - Ronald Koeman's touching tribute to Seamus Coleman
Speaking before Koeman's comments, O'Neill said that McCarthy was anxious to participate against Wales but added that his employer should look at why the 26-year-old is consistently having fitness problems.
"James wanted to play and he was fit to play," said O'Neill.
"He trained the last couple of days... if you're looking at the length of time he hasn't been with us and the times that he's missed either matches, either by not being picked or picking up a niggling injury, that's something the club and James will have to look at because we're not in control of him.
"If you look, he hasn't been with us now for a long, long time so what he does at club level is something that's outside our jurisdiction. We only have him on these days and we're guided by James, and our staff. The reason it seems to be more pronounced is because of the historical things seemingly between this country and Everton."
Relations between Koeman and O'Neill are poor, however. The Irish boss added that he put in a message to Everton recently via the press office giving his number so Koeman could call him to discuss McCarthy.
"There was no response," said O'Neill, who indicated that he did plan to give his opposite number a call to discuss Seamus Coleman's misfortune. That may change in light of Koeman's latest observations.