Jon Pollard has left City after more than 13 years as club secretary.
Pollard, who joined from Swindon in 1996, had previously worked for Norwich and Aldershot.
He plans to take a break back in his native Norfolk over Christmas before returning to the game in some capacity in the new year.
Stuart McCall admitted the loyal servant will be hugely missed behind the scenes.
“Jon does about five jobs all rolled into one,” said the City boss.
“He has been a great help to me with his in-depth knowledge on the football side of things.
“I must speak to him four or five times a day on all different aspects, whether it’s checking a player’s registration or sorting out the team hotel for away games. I rely on him so much and he will be a massive miss.
“I was really disappointed when I heard the news that Jon was leaving because he has been a great servant to this club.
“He does so much and it will be a big void to fill. But I wish Jon all the very best for the future.”
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