Niall McGinn is out of Northern Ireland’s friendly against Finland on Wednesday night.
And there are fears that the winger’s ankle injury may also rule him out of the opening World Cup qualifiers against Russia and Luxembourg in September.
McGinn’s home debut for Aberdeen was cut short when he was stretchered off 67 minutes into Saturday’s 0-0 draw at home to Ross County.
“Niall was included in the squad for midweek, but he won’t have any chance of going there because he has twisted his ankle,” said Aberdeen manager Craig Brown.
“I thought it was a head knock at first because he was holding his head, but I think that was just out of disappointment, not only from the point of view of his club but also the Northern Ireland team.
“We can’t tell the length of the recovery period, but he will certainly be out in the immediate future.”
Northern Ireland boss Michael O’Neill still has 22 players at his disposal for Wednesday’s game at Windsor Park, which is the last before the World Cup qualifying series begins in Moscow on Friday, September 7.
Rangers striker Andy Little will enter the game with his confidence boosted after scoring in the 2-2 draw against Peterhead on Saturday.