Duff and Phelps are evaluating three bids after American tycoon Bill Miller withdrew his offer earlier this week, just days after being named preferred bidder, and remain optimistic of a speedy sale.
Joint administrator Paul Clark said: "We have continued discussions today with the parties remaining in the bidding process and good progress has been made. We can also confirm that Craig Whyte has confirmed that he will transfer his shareholding in Rangers Football Club to two of the parties and has indicated he would not be an impediment to a sale of the club.
"We will issue a further update for supporters tomorrow and can say that every effort is being made to conclude the sale of the club as quickly as possible."
Press Association Sport understands one of the groups to have agreed a deal to take over Whyte's 85% shareholding is an English-based consortium.
The consortium held talks with Duff and Phelps on Thursday and Whyte is hoping the group can strike a deal to take over the Ibrox club by tomorrow ahead of attempts to exit administration through a Company Voluntary Arrangement (CVA).