Scotland international Stephen O'Donnell has rejected the chance to sign a new deal with Kilmarnock and will leave the Ayrshire club this summer.
The 28-year-old full-back, who has earned a club record-equalling 11 Scotland caps while at Rugby Park, is one of 12 players who are moving on.
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 are the others.
Kilmarnock 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'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 club and a good person to have around the place. As is the case with all the players, we thank them for their efforts and wish them all the very best."
Kilmarnock currently have 11 players contracted for next season including another Scotland international, Eamonn Brophy.
They remain in talks over new deals with five more, those being Chris Burke, Greg Kiltie, Jamie MacDonald, Rory McKenzie and Ross Millen.