The France midfielder is in his ninth year at Arsenal, but he is yet to start 100 league games for the club and missed all-but 16 minutes of last season with a cruciate ligament injury.
Diaby, who thought about retirement, has been able to play a full part in pre-season and featured in Saturday's friendly against New York Red Bulls.
And he said: "My love of football is just so big that I couldn't quit.
"I am still young and now that I have an oppportunity to play again I want to take it. I try to be positive all the time and that has helped me to come back.
"It is great just to be playing again. Now I just hope I can keep like this and continue. My knee is feeling good. I have been working hard on my fitness and strength.
"I am really confident I will be able to stay injury-free. I have worked hard for over a year."
Diaby also played 45 minutes of Arsenal's pre-season opener at Boreham Wood, and after that game Arsene Wegner said: "You wish that he just gets through the game, which happened here - I’m very pleased with that.
"If you get a fit Diaby back, it will be a major asset for our team. At the moment we go step-by-step and he came through this game so that’s very good news for us."
What Diaby actually means is "I can cash those free cheques for one more year by pretending I will actually play football".- Synergy
The guy is a decent footballer when healthy, sadly he is the original Mr Glass. Someone breathes in his direction and he breaks, strains or pulls something.