De Zeeuw, 37, and Jackson, 35, were expected to renew their contracts in the summer after their impressive recent form, however a last minute change of heart by both players has left manager Paul Jewell a little bemused.
Jewell told the club's official website: "I'm upset to be honest. Both players are great pro's and it seemed as though everything was agreed until a last minute change of heart. Both Arjan and Matt have worked extremely hard for me as manager and I wish them well for the future."
It is unclear what caused the last minute change of heart although one rumour going round is that both players have been subject to a better offer from local neighbours Bolton Wanderers.
Watch this space for updates.