The Dublin-born player joined the Pittodrie side in the summer from Peterborough United, but made just eight appearances for the Dons.
Forrester scored what turned out to be the winning penalty in the Betfred Cup quarter-final clash against Hibs.
The former Bohemians and St Patricks Athletic man will return to his homeland following his release from Aberdeen.
Manager Derek McInnes said: “It’s with a lot of sadness and regret that we’ve terminated Chris’s contract. At his request we’ve allowed him to be back with his family in Ireland.
“He’s had a lot to contend with in his personal life and as a club, we have an understanding of the situation and we wish him well with his future career.”
A statement from the Dons read: “Aberdeen Football Club can confirm we have agreed to terminate Chris Forrester’s contract. Everyone at the club wishes Chris all the very best in the future.”