Hull City's Alex Bruce has been ruled out of the Northern Irish squad ahead of their World Cup qualifier in Portugal next week.
Bruce was called into the squad by Michael O'Neill for the first time, after he confirmed he was switching allegiance from the Republic of Ireland.
However, a groin problem means that Bruce will not now be in line to make his debut against Portugal - which is live on Sky Sports 1HD on Tuesday.
Confirming the news, Bruce Tweeted: "Gutted I've came home from Portugal yesterday.
"The groin strain I picked up playing for Hull still isn't right, hope the lads get a result."
Peterborough's Grant McCann has also been ruled out with a knee injury and has also returned to his club.
Manager Michael O'Neill has not called up any replacements at this stage.