Annan who was third choice goalkeeper in the 2020/21 football season has mutually parted ways after successful negotiations with the management of the club.
In an emotional farewell message to the club, Annan said: “In the last couple of weeks, I have been engaged in a very emotional conversation with management and the Board of Directors concerning my future.
“After several consultations, it was resolved that my desire to continue my career path elsewhere after 10 years of dedicated service to Asante Kotoko to be respected by all.
Annan thanked Asantehene Otumfuo Osei Tutu II, the board and management, the technical team, playing body and the fans of the club for their support during his stay at the club.
He added that he would forever cherish his time in the Kotoko family after a successful career with them.
Annan started his career with then Gomoa Fetteh Feyenoord now known as West Africa Football Academy and joined Kotoko back in 2011.
Annan made over 120 appearances for the club having won the Ghana Premier League, FA Cup, among others.