The Gunners lost their captain Cesc Fabregas as well as Gael Clichy and Samir Nasri, while the Frenchman managed to clinch the signings of Per Mertesacker, Yossi Benayoun and Mikel Arteta on the final days of the transfer window.
Following the squad overhaul, the 61-year-old has hinted that the new additions may not have been brought in if some key players had remained at the Emirates.
"It was all change in the summer and some of that was for unwanted reasons," Wenger told the club's official magazine.
"We lost some players that we didn't want to lose, also we had some players that hadn't played for a while, so we thought it was important to renew the whole squad, and that's what we did."
The Gunners take on Sunderland in the Premier League this Sunday.