Ashley stated earlier this week that he has never been closer to selling Newcastle.
Newcastle have pushed themselves into a much more respectable 14th place after picking up 10 points from the last possible 15, but beforehand things looked a lot darker.
The club have managed to score just 12 goals in 15 Premier League games, while a new left-back, central midfielder, number 10 and a winger are positions that fans want to see strengthened.
Owner Mike Ashley told fans that he has never been closer to selling the club, but former Toon star Cassidy said that players have told him they do not expect Ashley to fund new signings in the January transfer window.
"I go over to the training ground now and again," Cassidy said. "Even the players of today know they need players in. It's not very often in the past where players have attacked each other.
"But some of the Newcastle players who play today have told me they need three or four players in, but they don't think the chairman will pay the money for them. So that's a negative which frightens me.
"A couple of bad results and we could struggle badly for the rest of the season."
Newcastle are reportedly close to completing the signing of playmaker Miguel Almiron from MLS outfit Atalanta United, with a fee touted at around the £15million mark - the biggest under Rafa Benitez's tenure.
It remains to be seen if Ashley will still be the club's owner come the start of the January window, with the Sports Direct mogul claiming in the interview that he could sell up by the end of December.
Newcastle are next in action against newly-promoted Wolverhampton Wanderers at St. James' Park on Saturday, in what could prove to be a crucial clash at the bottom of the table.