Aaron Connolly is a doubt for Ireland’s games with New Zealand and Denmark with a groin problem.
The Brighton player suffered the injury in the first half of Brighton’s loss to Manchester United and was replaced at half time.
And, he has now remained in the UK to have a scan rather than join up with the squad.
Boss Mick McCarthy said: “Aaron will have a scan on Monday morning.
“Our medical team have been in contact with Brightonand when we have their results, we will know more.”
His potential absence is a worry for McCarthy who was relieved that the rest of his 28-strong squad all came through the weekend unscathed.
Darren Randolph returned to action after a three-week layoff with a thigh problem to prove his fitness ahead of the game.
Glenn Whelan has also overcome a hamstring problem that forced him off in Hearts’ loss to Rangers last week though he was an unused substitute against St Mirren on Saturday.
McCarthy has also confirmed that Shamrock Rovers star Jack Byrne will face New Zealand on Thursday.
New call-ups Troy Parrott and Lee O’Connor will also see action against New Zealand though McCarthy is expected to keep his regulars in reserve ahead of the must-win Denmark game.
Ireland need to beat the Danes to qualify automatically for Euro 2020 while the visitors are likely to come to Dublin only needing a draw.