Zaccardo won the Bundesliga with Wolfsburg last season.
“I wanted to play in Italy so I am happy to be here,” he explained.
“I would like to thank President Tommaso Ghirardi and Pietro Leonardi for this, as well as the Coach who really wanted me to play for him.
“With Wolfsburg I could have played in Champions League but I left because I love this job and I always follow my heart.
“My experience is now at the service of this team and I am hoping to settle in promptly. Our target is survival and I want to achieve it.
“Francesco Guidolin is the Coach who knows me best because he had me at two different clubs, Bologna and Palermo. We have an exceptional relationship and I trust him.”