Arsenal manager Arsene Wenger has admitted that the severity of Abou Diaby's injury shocked him.
Diaby was ruled out for up to nine months after tearing his anterior cruciate ligament earlier this week, the latest in a long line of injuries for the midfielder.
Wenger didn't believe that the injury was so serious at first, and admits that the news was "demoralising" for both the club and the player.
"That was the shock of the week for us, because I thought originally it was just a little twist of the knee," said Wenger.
"When they told me it was a rupture of his cruciate, and when you know what this guy has gone through, how many times he has worked day and night to come back in rehab, it is just demoralising.
"I hope he will find the resources and the strength to come back because he was quite down."
Arsenal currently sit fifth in the Premier League table, two points off fourth-placed Chelsea after today's 4-1 win over Reading.