The Frenchman has spent much of the last two seasons on the treatment table with a variety of problems, and only featured four times for the Gunners in the 2012-2013 campaign.
However, he has started all three of Arsenal's Premier League fixtures this year, and put in a man-of-the-match-winning display against Liverpool last weekend.
Although he has admitted that his lengthy layoff came with some "difficult moments", Diaby is happy that he has returned strongly at a vital point in his career.
"I had some very difficult moments, some days when I was depressed when it was tough, but even then, I always kept faith," said Diaby.
"I always told myself that some people were in a worse position than me. I am 26 and I am aware that I am at a key moment in my career, that is why it was so important that I came back this season."
Diaby joined Arsenal from Auxerre in 2006 and has made 114 appearances for the club.