Stephen O’Donnell will leave Kilmarnock when his contract expires at the end of the month.
The Rugby Park outfit confirmed the defender’s departure on Tuesday, adding they had tried their best to keep him.
The Scotland international has been a mainstay in the team since joining from Luton three years ago.
Manager Alex Dyer said: “It is never easy to see players depart the club, especially in these circumstances, where the guys have not had the chance to say goodbye to the crowd and the fans have not had the opportunity to thank the players for their contribution.
“In Stephen O’Donnell’s case, we tried our very best to keep him and spoke on numerous occasions both in person and on the phone but he wants to explore his options as he’s entitled to do as a free agent.
“Stephen has been a fantastic player for this football club and a good person to have around the place and, as is the case with all the players, we thank them for their efforts and wish them all the very best for the future.
“To our supporters, I hope you are all keeping safe and well and we’ll continue to keep you up-to-date with any more news as soon as possible.”
O’Donnell is not the only departure in Ayrshire, with a number of players due to leave at the end of their contract or loan period.
These include Laurentiu Branescu, Harry Bunn, Dario Del Fabro, Adam Frizzell, Niko Hamalainen, Stephen Hendrie, Connor Johnson, Jan Koprivec, Devlin Mackay, Harvey St Clair and Iain Wilson.