As well as Whittle, the players departing are Melvin Minter, Fraser Kerr, Curtis Weston, Joe Rowley, Stefan Payne and Nathan Tyson.
Whittle’s departure will come as the biggest shock to Town fans after the Player of the Year contender’s consistent season at left-back.
There may also be a few raised eyebrows at Gavin Gunning, Laurence Maguire, Calvin Miller and Akwasi Asante all being transfer listed. Maguire is Chesterfield’s longest-serving player.
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New contracts will be offered to Luke Croll, Jim Kellermann, Jak McCourt and Tom Denton.
George Carline and Haydn Hollis, who are also out of contract and have had long-term injuries, have been invited to continue their rehabilitation at the club and could still possibly earn themselves new deals.
The following players are still under contract: Scott Loach, Jeff King, Tyrone Williams, Maguire, Jamie Grimes, Gunning, Jack Clarke, Saidou Khan, Tom Whelan, Liam Mandeville, Miller, Manny Oyeleke, Joe Quigley, Danny Rowe, Kabongo Tshimanga and Asante.
“The club would like to thank those who are leaving for their service and wish them well for the future,” the Spireites said.
Following his departure, Rowley posted on Twitter: “8 years and out. Thank you to many great people along the way, staff, players and especially the fans. A club I’ll always love, now onto the next chapter.”
All signs point to a big summer of change at Chesterfield after losing in Sunday’s play-off semi-final against Solihull Moors, resigning them to a fifth successive season in the National League.
Cook has said on more than one occasion that he was struggling to ‘trust’ some of the players and that their decision-making was ‘mind-boggling.’