Glentoran defender Colin Nixon has been informed that he will not be offered a new contract by the East Belfast club.
The 34-year-old made his Glens debut in 1995 and is the Oval club's longest serving player, having made a record 792 appearances, scoring 87 goals.
Nixon has won four league titles and five Irish Cups during that period and could pick up another winner's medal in the Irish Cup final on 4 May.
The defender does not intend to retire and will seek a new club in the summer.
"It came as a bit of a shock to me and to be honest I'm absolutely devastated," said Nixon.
"I don't really understand the decision as I still feel I have a lot to offer as a player and I had hoped to have some sort of role at the club beyond my playing days.
"I just have to pick up the pieces now and look for a new challenge."