Dan Cleary has left St Johnstone due to family reasons.
Manager Callum Davidson said he was “gutted” to lose the centre-half but thanked him for his service.
The 26-year-old, who arrived back in January after leaving Dundalk, helped Saints keep hold of their Premiership status for this coming season.
Davidson confirmed: “Dan is away back to Ireland and I’d like to thank him for everything he did for us.
“He came here when we were struggling and played a part in keeping the club in the Premiership.
“I am gutted to lose him but family is more important and he’s got to do what’s best for them.
“We had a few chats over the last few days and it was obvious how much he wanted to do well here.
“It’s a tough time for him and we all wish him all the best for the future.”
Davidson has moved to welcome a new centre-half in 20-year-old Alex Mitchell on loan from Millwall.