Scotland forward Ross Stewart has been ruled out of action for up to eight weeks after suffering a thigh injury.
The 26-year-old will now miss the Nations League games against Ukraine in a double header and Ireland at Hampden at the end of this month.
The Sunderland star, who has five goals in seven games in the English Championship this season, picked up the injury as he was preparing to play Middlesbrough in Monday night’s Tees-Wear derby.
He was forced to pull out of the game that ended in a 1-0 defeat and a scan later revealed significant damage to a thigh muscle.
He now faces a period of rehabilitation which his manager, former Celtic and Hibs boss Tony Mowbray, says could keep him on the side-lines for around two months.
Stewart made his Scotland debut by coming on as a sub in a 2-0 win over Armenia in Glasgow in June before again coming off the bench for his second cap in the 3-0 defeat to Republic of Ireland in Dublin.
He earned the call up to Steve Clarke’s squad following an impressive season in England’s League One where he scored 26 goals across all competitions and helped Sunderland gain promotion.
After starting this season in similar form he was bound to have been in Clarke’s plans again when the national team is back in action later this month.
Mowbray told the Sunderland website: “Ross will be out for six to eight weeks – it could be a little longer, but that will depend on his rehabilitation and the way his body reacts.
“He’s a really positive guy and we hope that he will be a quick healer, so we will take it game by game and hopefully he returns quickly.
“It is a blow and now we have to find a way to score the goals, but we will be positive and we will not be all doom and gloom about how we are going to win games and score.
“There are players within the squad who are capable of stepping up and our job is to find a way to win, so that’s what we will do.”