Middlesbrough winger Mustapha Carayol is set to be sidelined for up to four months with a knee injury.
Carayol has started just two league games since moving from Bristol Rovers in the summer, but he has already impressed.
However, he now looks unlikely to play again this year after damaging his knee - which needs surgery.
Carayol will go under the knife next week and looks unlikely to play again before 2013.
The news will be a huge blow to Tony Mowbray, who has already lost captain Rhys Williams and Curtis Main to long-term injuries in recent weeks.