Andrew Little has been called into the Northern Ireland squad after Kyle Lafferty and Martin Paterson pulled out.
Northern Ireland coach Nigel Worthington has been forced to promote Little from the Under 21 squad for the 2010 World Cup qualifiers against Poland and Slovenia.
Rangers striker Lafferty, who was due to miss the Poland game through suspension, is now out of the Slovenia game due to an ankle problem.
Burnley forward Paterson will also be absent for the two games with a hamstring injury, while Celtic's Pat McCourt has withdrawn.
Lafferty's Rangers team-mate Little has been drafted into the senior squad after scoring once in four appearances for the Under 21s.
Little has yet to make his first-team debut for Rangers and will provide Worthington with attacking cover for the home games with Poland and Slovenia.