Diaby has struggled to stay injury free since sustaining a fractured, dislocated ankle in 2006. Last campaign the France international managed just 13 Premier league starts for Arsenal.
The former Auxerre midfielder has now undergone surgery on a troublesome ankle problem, meaning he will miss the start of the new season.
Wenger told the club's official website: "Abou had ankle surgery during the break. Normally he should be back eight to ten weeks after his surgery, which means the end of August."