Crewe Alex boss David Artell, speaking to Cheshire Live, says the Spireites could be facing 'oblivion' after successive relegations and a poor first half of the National League season.
Town sit third from bottom and this week parted ways with manager Martin Allen.
"You look at Chesterfield now, and that could be oblivion," said Artell, who was appointed as Crewe Alexandra's first team manager in January 2017.
"If they go in the Conference North, wow. That's a huge club with a brilliant stadium and a good fanbase. It's frightening really, I can't believe they went down last year.
"They had a big budget, certainly a lot bigger than ours, I thought they'd get some players in. But they just never arrested that slide, and it's continued."
Artell says he's been in contact with Allen recently but wouldn't offer an opinion on whether or not the manager should have left the Proact this week.
"It's another manager who loses his job, but that's the name of the game. It's not easy," he said.
"I spoke to Martin Allen two or three times over the last two or three weeks. I'm not sure whether he should have paid with his job or not, it's not for me to say, but I do think it shows that mismanagement at any level makes it very difficult to stop that slide."