Glentoran have "reluctantly" put Sean Ward on the transfer list after the defender requested a release from his contract with the east Belfast club.
The 29-year-old started in the Irish Cup final success against Cliftonville but has decided his future lies elsewhere.
The club said it expected to announce contract extensions for a significant number of players.
Striker Andy Waterworth left the Glens to join rivals Linfield last week.
Waterworth scored two goals in the 3-1 victory over the Reds in the Irish Cup decider earlier this month.
Ward handed in a written transfer request and he has been placed on the list with immediate effect.
"We are naturally disappointed to be losing a player of Sean's calibre and experience and wish to thank him for the significant contribution that he has made to our club," said Glentoran.
"We also wish Sean well with whichever club successfully negotiates his transfer."