The 26-year-old suffered the injury in training Wednesday and is due to undergo surgery, reports Xinhua.
"Abou Diaby injured his left knee in training Wednesday and subsequent scans have confirmed that he has torn his anterior cruciate ligament," the English Premier League club said in a statement Thursday.
"Following consultations with specialists, Abou will undergo surgery to repair the injury in the near future. He is expected to be out for around eight to nine months."
--IANS (Posted on 29-03-2013)