Middlesbrough have confirmed that winger Mustapha Carayol has torn his anterior cruciate ligament.
The 25-year-old picked up the injury against Bournemouth at the weekend, but the club have been awaiting reports on scans in London.
Now the club have have confirmed their worse fears that Carayol has torn his anterior cruciate ligament.
A club spokesman said: "Following scans and consultations in London, it has been confirmed that Muzzy Carayol has torn his anterior cruciate ligament.
"He will be operated on by world-renowned English specialist Andy Williams in two weeks' time once the swelling has gone down."
Carayol will go under the knife before undergoing his rehabilitation, with the hope that he could be fit in time for next season.