The administrators have been in talks with manager Ally McCoist about trimming the playing squad but delayed any decision until next week.
"The Rangers business is trading at a substantial loss and we have no alternative but to fill an approximate 4.5 million pounds shortfall by the end of the season," joint administrator Paul Clark of Duff and Phelps said in a statement.
"It is therefore imperative we find savings of approximately one million pounds per month to ensure the ongoing viability of the business."
The financial crisis facing Rangers, league champions a world record 54 times, has sent shockwaves through British football where many clubs are living beyond their means.
In England, the administrator for Portsmouth warned on Thursday the Championship club could fail to fulfil their remaining fixtures this season because of a shortage of cash.
Rangers and Portsmouth have fallen behind on tax payments, forcing them into administration.
The Scottish champions owe around nine million pounds in payroll and sales taxes. They also face a potential liability of more than 50 million pounds in a separate tax case relating to how players were paid in recent years.
Rangers have been docked 10 points for going into administration, effectively handing the league title to city rivals Celtic.
