Chelsea's Michael Essien has been ruled out English Premiership football action for more than five months after rupturing an anterior cruciate ligament.
The midfielder suffered the injury during Ghana's World Cup qualifier against Libya in Tripoli last weekend.
Essien will undergo surgery once the swelling around his knee has subsided.
Essien has been a regular for Chelsea since his 63 million dollar move from Lyon in 2005, scoring 14 goals in 132 appearances.
The loss of the combative Ghanaian for such a long period is a major blow to Chelsea, who have no like-for-like replacement available and will not be able to buy any fresh faces before the transfer window re-opens in January.