Administrators Duff & Phelps had hoped to accept an offer this week but have now had to inform bidders of a possible change in the Glasgow club's situation with the Scottish Premier League considering points deductions in the next two seasons.
Second-placed Rangers, Scottish champions a record 54 times, were deducted 10 points in February for going into administration over unpaid tax bills and city rivals Celtic won the league title last weekend.
Paul Clark, joint administrator, said in a statement: "As administrators we had hoped to announce today the acceptance in principle of an offer for the purchase of Rangers Football Club, which would be followed by a period of exclusivity while due diligence is undertaken.
"Regrettably, this is not now possible as we were informed over the Easter holiday period that the SPL is proposing to consider at a general meeting on April 30, significant rule changes in relation to clubs which find themselves in an insolvency situation."
An SPL statement said the April 30 meeting would consider "further sporting sanctions in the event that any club undergoes an Insolvency Transfer Event of 10 points in each of two consecutive seasons from the Insolvency Transfer Event" among other proposals.
Clark said the development was "disruptive and regrettable".
The three bidders include the Blue Knights consortium, headed by former Rangers director Paul Murray.
"The effect of such revised measures being considered at this juncture is that we, as administrators, are duty bound to inform those parties who have submitted bids of the proposed resolutions the SPL intends to consider," Clark added.
"Inevitably, bidders are now considering this information and will have to take a view as to whether it will affect their individual bids as they now stand. The result is a delay in the sale process.
"We hope to receive feedback from bidders as soon as possible in order for us to take the sale process forward as quickly as we can."
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