The 35-year-old will return to his family in England and is keen to move to a club closer to his home.
Duberry told the Saints’ official website: “It’s been great seeing the wife and kids every day since the end of the season.
“I’ve been doing the school run and it’s little things like that which I’ve really missed.
“That’s swung me towards finding a club nearer home and I hope the fans understand.
“I had a great time with St Johnstone, they gave me a platform in the SPL which raised my profile and the fans were great to me. I will miss them and the club.”
