Kenny Cunningham has failed to overcome a hamstring injury and will miss the Republic of Ireland's friendly international against Scotland at Hampden Park tomorrow.
The defender has returned to his club, Birmingham City, for treatment.
Cunningham took no part in yesterday's training session, after having played three times in just eight days for his club despite returning recently from injury.
Ireland manager Brian Kerr confirmed that the 31-year-old would have captained the side had he been fit.
Kerr already has a new captain in mind for tomorrow's game but said the player had not been told yet. "I will tell him early in the day," said the manager.
Southampton's Rory Delap has returned home for personal reasons.
Full back Steve Finnan has a heavy cold and will miss tonight's training session.
Kerr will delay naming his team until tomorrow morning at the earliest.
"I have a team and I will tell the players tomorrow and then I will let everyone know," he confirmed.
"But I have a couple of little problems. If the Steve Finnan situation is sorted then I have a clear team in my mind."
Kerr and his Scotland counterpart, Berti Vogts, have agreed to use eight substitutes.
