Jonny Evans is a doubt for Northern Ireland's friendly against Albania after sitting out training on Monday evening.
The defender picked up a knock to his knee when playing the 90 minutes of Manchester United's Carling Cup victory over Aston Villa on Sunday.
Evans travelled out to Albania with his international team-mates on Monday and was then given time to rest by coach Nigel Worthington.
He will be re-assessed on Tuesday before a decision is taken on his participation and as a precaution Worthington has called up Jonny's 19-year-old brother Corry, who is also on the books at Old Trafford.
Corry is currently in San Marino with the Under 21 squad for a European Championship qualifier and will join up with the senior squad on Wednesday.
Worthington is short of defenders, with Fulham duo Aaron Hughes and Chris Baird both rested and Ipswich's Gareth McAuley injured.
McAuley was one of four players to withdraw from the squad to face Albania, with Chris Brunt, Damien Johnson and Warren Feeney also pulling out.