Arsenal midfielder Abou Diaby will be out for eight to nine months after tearing his anterior cruciate ligament in training.
"Following consultations with specialists, Abou will undergo surgery to repair the injury in the near future," a statement on the Premier League club's website said today.
"Abou is expected to be out for around eight to nine months."
The Frenchman has been plagued by injuries at Arsenal, missing most of last season with ankle and calf injuries. In 2006 he fractured and dislocated his ankle.
Diaby's injury setback means Arsene Wenger is without several first-choice players in their efforts to secure a top-four finish in the Premier League.
Jack Wilshere is also sidelined for two weeks while Theo Walcott will not feature against Reading on Saturday.
Wilshere will not be rushed back into action, says Wenger. He has not played since Arsenal's defeat at Tottenham on March 3rd after he was rested because of an ankle problem. He was initially expected to feature against Reading following a rehabilitation schedule which included a trip to Dubai.
However, Wenger said today Wilshere would be out for at least another two weeks, while Walcott is also set for more treatment on what was described as a "minor hip/groin injury" picked up training with England ahead of the San Marino World Cup qualifier.
"Wilshere's injury is not better or worse. It was an inflammation of his [ankle]bone and we had such history with him [that] we are a bit more cautious than we would be with you or with me," said Wenger. "We deferred a little bit his rehab by one week. We gave him one more week's rest because it was wise medically to do it.
"Honestly, it's very difficult [to say when he will be back]. I believe in two weeks on Sunday, that means not the next game, the game after."
Wenger insisted that given Wilshere's injury record, having been sidelined for more than a year with a different ankle problem, the club's medical staff would take no chances.
"We will rest him when it is needed. He has regular scans and as soon as we have an alert we will respect it no matter what is at stake," Wenger said. "Jack had a difficult moment of course when you told him because he didn't feel any special pain, but he knows he has to take care of his future. Because he is a very young player, I think he accepts it."
Wenger added: "The country doesn't depend on one player, no matter how good he is. I believe what is the quality of a country is the number of good players they have. Jack is a fantastic player, but it would be too much pressure on him to say England's future depends on him."
