Arsenal confirmed Diaby's injury on their official website, stating: "Following consultations with specialists, Abou will undergo surgery to repair the injury in the near future. Abou is expected to be out for around eight to nine months."
"The thoughts and best wishes from everyone at Arsenal are with Abou, and we all wish him a successful recovery."
Diaby has been plagued with injuries throughout his time at Arsenal and as such has suffered several setbacks and subsequent false dawns, but this injury, his most serious for some time, could spell the end of his Arsenal career. The news also leaves Arsenal short in midfield as they bid to overhaul a four-point deficit with fierce rivals Tottenham Hotspur to claim the last Champions League spot in the Premier League.