Nottingham Forest now fear striker Nathan Tyson could be out for up to six weeks through injury.
Tyson suffered a hamstring problem after scoring the winner in Saturday's League One game with Swindon Town at the City Ground.
Forest boss Colin Calderwood was initially hoping that the forward would only require three weeks on the sidelines.
But Calderwood has now conceded that the 25-year-old could be out of the club's promotion push until April.
"I would imagine that Nathan will be out for four to six weeks with a hamstring strain or tear," Calderwood told the club's official website.
"We can without him, and we will have to, but the important thing is we get him back fit and well for the final run-in."