Gunners boss Wenger had been unwilling to set a comeback date for the England midfielder, who has already been out for a year with ankle and knee problems.
But, speaking ahead of Arsenal's final match of their Asia tour in Hong Kong on Sunday, Wenger said: "Hopefully, we will get Wilshere back playing for October.
"With Abou Diaby returning, it will be like signing two new players. This season, the squad will be strong and competitive."
Wilshere, who will reportedly resume light training next month, underwent a procedure on his knee in May, having missed the whole of last season with an ankle problem.
An October return would rule him out of England's opening two World Cup qualifiers against Moldova and Ukraine, which take place in early September.