Rangers are without a permanent manager after Michael Beale was sacked after poor displays both domestically and in Europe.
They have been interviewing candidates but are yet to take a final call on an appointment, with a decision expected over the course of the international break.
McManus, while comparing the two Glasgow giants and their success over the last decade, insisted that the new Rangers manager will have some demands to make to the board before taking over.
With the challenge being to topple Celtic and win the league title, McManus believes that money will have to be made available in January in order to make signings.
“I think the Rangers job is a difficult job, you have got to topple Celtic”, McManus explained on PLZ Soccer.
“It has been shown over the last ten, eleven, 12 years that it is very, very difficult, bar one season when Rangers won the league, Celtic have absolutely dominated.
“I think the first thing he [new Rangers manager] is going to ask is how much money I have got, because Celtic have got plenty of money, I need to sign four, five, six players in January that are going to be better than what we’ve got here. That requires money.
“He is going to have to get a big pot in January, otherwise you might have second thoughts about taking the job.
“I am not saying it is a poisoned chalice, but it is a very difficult ask at the minute for a Rangers manager to come in and topple Celtic with Brendan Rodgers and the money, they have got behind them.”
Rangers are currently being managed by caretaker manager Steven Davis, who has led them to one 3-0 victory in the league over St Mirren and suffered an away defeat in the Europa League against Aris Limassol.
