Fulham defender Aaron Hughes has emerged as a doubt for Northern Ireland's World Cup qualifier against Portugal on Friday.
The 33-year-old, who had been expected to start at right-back, picked up a groin injury during his club's defeat to Newcastle United at the weekend.
It is understood that the versatile defender will join up with the squad on Wednesday evening, but it is unclear whether he will be considered for selection.
Craig Cathcart has also been ruled out with a knee injury.