Martin O'Neill believes James McCarthy would have played in Ireland's game against Scotland in Glasgow on Friday night had it been a club fixture.
McCarthy ended Everton's game last weekend against Sunderland with concerns about a hamstring injury but after a couple of days of monitoring with the Ireland squad, he returned to his club on Thursday, even though the scan on the injury had been clear.
"At club level I think we could have afforded to risk him in the game tonight," O'Neill said after Ireland's defeat at Celtic Park on Friday.
"I know as a club manager if you think a scan is clear on a certain day then you would have to give that consideration, maybe more than we're able to.
"But psychologically it's important as well too that a player feels it's all right and that's always a consideration you take in," O'Neill added.
McCarthy missed Ireland's two games against Gibraltar and Germany in October with a hamstring problem but returned to play for Everton the following weekend and O'Neill expects McCarthy to be fit for his club again next weekend.
"James was getting better every single day and I'm quite sure he'll be available to play for Everton next weekend but if you haven't done the work beforehand . . .
"We were hoping that James might have been able to have done something. It was important for us that he did some work on Thursday but it wasn't going to be the case so we thought, 'Well, we must leave it now', because he might last two minutes in the game.
"At club level, he belongs to the club and it's their prerogative to do what they want."
McCarthy and Aiden McGeady had been the focus of attention in the build-up to the game as they were expected to receive a hostile reception. McGeady was booed every time he touched the ball on Friday night and gave an unconvincing display.
O'Neill dismissed the speculation that McCarthy, who was at the game on Friday night, didn't want to play against Scotland, the country of his birth.
"He wanted to play absolutely," he insisted.
Robbie Keane was dropped for the first time in 13 years for Ireland against Scotland and O'Neill has decided to allow him to return to Los Angeles before Tuesday night's game against the USA. "We can try some of the lads now that I can bring in," the manager said.
McCarthy's Everton team-mate Darron Gibson has also withdrawn to receive treatment on a minor knee injury.
Sunday Indo Sport
I will always remember the parting words of my club manager as I headed off to international duty with the Republic of Ireland youth team many years ago. I had previously read his public remarks that he was pleased for me and that he thought it would be good for my career development.
It was a bloody awful game to lose because it was a bloody awful game full stop, one which looked less like an international match than a local derby in the Championship. And when I say Championship I mean the second flight of English football, though the ball spent so much time in the air on Friday night we might have been in Croke rather than Celtic Park. We'd been promised blood and thunder. We got thud and blunder.