Wes Hoolahan has added to the Republic of Ireland's concerns ahead of the Euro 2016 qualifier with Germany on Thursday night at the Aviva Stadium.
The Norwich midfielder missed training this morning in Abbotstown due to a heel injury, while Everton's Seamus Coleman also sat out because of the hamstring problem that has ruled him out of action for the last number of weeks.
Cyrus Christie, who could yet deputise for hamstring victim Coleman, did train after recovering from a groin strain but the management team will keep their collective fingers crossed as they await news on their walking wounded.
Assistant manager Roy Keane said: [Wes] has a knock on his heel from the weekend and it's pretty sore.
"The fact he didn't train today tells you it must be sore.
"Again, we'll see how that goes over the next 24 hours."
Asked whether it a worry that Ireland could be without a number of players to face the world champions, with Glenn Whelan and James McClean also suspended, Keane said they must cope with the situation.
He stated: "That's life isn't it? You just have to get on with it.
"We had it from day one. Most managers and staff in international football will tell you the problem is you turn up and [have] the injuries and suspensions we've got this week. That's part of the game.
"I think with Wes' injury another 24 hours will make a big difference to it. Obviously Seamus hasn't kicked a ball for three or four weeks now so he would be more of a concern. We'll see how it goes."
Keane did confirm that he expects to expects his namesake Robbie to be available for selection days after becoming a father for the second time.
The 35-year-old Los Angeles Galaxy striker was not due to arrive in Dublin until Tuesday evening after his wife Claudine gave birth to the couple's second son on the other side of the Atlantic.
Roy Keane is confident Robbie Keane will be available on Thursday: "Unless he's breastfeeding he should be alright." https://t.co/E3qSujoXUT
— RTÉ Soccer (@RTEsoccer) October 6, 2015
Asked if his former team-mate would be available for the showdown with Group D leaders Germany at the Aviva Stadium, Ireland's assistant manager said: "Yes, why wouldn't he be?
"He didn't have the baby. Unless he's breast-feeding he should be all right."
Frontman Keane was part of the team which secured a 1-1 draw with the world champions courtesy of John O'Shea's injury-time strike in Gelsenkirchen in October last year, and a repeat at the Aviva could have a major say in whether or not they make it to the finals in France next summer.
That result came amid an uncharacteristically slow start to the campaign by Joachim Low's men, who have since put together a run of five successive qualifier victories.
However, while former Manchester United captain Keane admits they will be a different proposition this time around, he is confident Ireland have improved too.
He said: "I think we are a stronger team. Like you'd expect with any campaign, teams improve. We were still new to the job at the time and, yes, I think we are a better team.
"But certainly Germany's form, as you would have expected - they were a bit sluggish at the start, but with all the qualities they have it was only a matter of time before they started winning matches and topped the group, no doubt.
"But we will be ready."
Ireland go into an intensely difficult double-header - they face second-placed Poland in Warsaw on Sunday evening in their final game - knowing victory in just one of those matches will guarantee at least a third-place finish and a play-off spot.
However, they are equally aware that should Scotland, who currently trail them by four points, beat both the Poles and Gibraltar, even creditable draws against the Germans and in Warsaw will see them miss out.
O'Neill's number two said: "I've said it before, this is what the players and this is what we are in the game for. It's a big game, we are playing quality opposition. This is what it's all about."
Meanwhile, former Aston Villa assistant boss Keane adopted a similar stance to that of O'Neill over Jack Grealish's decision to opt to represent England rather than Ireland.
He had tried to persuade the 20-year-old to continue to play for the nation he has represented at age group levels up to Under-21 during their time together in the Midlands, but ultimately accepted his decision to chose the country of his birth.
O'Neill had earlier launched a stern defence of his handling of the situation, insisting he had not prostituted himself in a bid to land the youngster, and asked if everything had been done that could be done, Keane said: "Yes, absolutely. What more can you do?
"I think the manager did everything he could. Jack was already playing for Ireland and you were hoping that he'd continue. That's life, you move on."
