Peterborough director of football Barry Fry is predicting the most challenging period of his 21 years at the club.
Midfielders Michael Bostwick, 28, and Marcus Maddison, 23, are among seven players transfer-listed to avoid them leaving for free next summer.
"We're not in a position to increase anybody's contract at this moment," Fry told BBC Radio Cambridgeshire.
"The gates have fallen, season tickets are a disaster. It's the biggest challenge since I've been here."
Peterborough chairman Darragh MacAnthony later tweeted to confirm the club was 310 season ticket sales down on last season, clarified by the club as a financial shortfall of £57,000.
Bostwick, who has made 228 appearances for Posh, and Maddison - recently described by boss Grant McCann as "on his day, one of the best in this league" - could both be sold if they do not accept similar terms to their current deals.
Lee Angol, Jordan Nicholson, Jerome Binnom-Williams, Hayden White and Luke James have also been made available as they are also in the final year of their contracts.
"We've got too many players in the squad," Fry said. "If we get rid of who we want to get rid of, then it could be a different matter."
Leeds 'moved the goalposts' over Maddison
Fry said Leeds were interested in signing Maddison in January 2016, but claimed negotiations broke down over the transfer fee.
He continued: "I had three meetings with Leeds and thought I'd agreed a fee, then [Leeds owner Massimo] Cellino changed the goalposts and it didn't happen.
"Marcus was disappointed it didn't happen, obviously, because Leeds are a huge club.
"He's in his last year and we'll see what comes in, but we won't be selling him for the sake of selling him."
Fry, whose involvement with Posh began when he took over as chairman and manager in 1996, said Bostwick was appreciative of the club's policy of transfer-listing those with a year to run on their deals.
"The chairman spoke to him and he's happy about that," Fry said.
"Michael's been a magnificent servant to Peterborough. If nothing happens, we're quite happy to keep him and if he's not gone by the start of next season, we'll talk to him about an extension."