Diaby has undergone more surgery on his cruciate knee ligament after a setback in his recovery from the injury.
Arsenal midfielder Diaby, 27, suffered the injury in March and is now facing 12 months on the sidelines which is another hammer blow for the French international whose career has been dogged by injuries.
Gunners boss Arsene Wenger said: "He had a little key hole surgery again, on the knee because his knee blew up every time he did something so it is now six months after the cruciate.
"He could not even jog yet so with new surgery it is a set back for him so competitive football cannot be played before March."
It was widely expected to be the last season of Diaby's career at Arsenal but Wenger insists that he may get another chance.
Wenger added: "He has one and a half years to go on his contract."
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