Sale Sharks owner Brian Kennedy has warned Rangers' administrators they must accept the Blue Knights' offer for the club on Friday or they will walk away.
Kennedy has reportedly struck a deal with Craig Whyte to acquire his 85% shareholding and will now push Duff and Phelps to name a bidder.
The Blue Knights were previously offered preferred bidder status but former partners Ticketus would not pay the exclusivity fee and they were then beaten by Bill Miller, who withdrew on Tuesday.
Kennedy told the Daily Record they were now at the "end of the road''.
"If our bid is not accepted in the next few hours then, most reluctantly, we will have to withdraw from the process by lunchtime,'' he said. "Let me be absolutely clear. This is not brinkmanship or an empty threat.
"We have a plan to save this club but my lawyers, Walker Morris, have advised me it will not be possible to execute a CVA unless, on Saturday morning, we begin working, full-time and flat out on due diligence and documentation.
"Any later than that and our plan cannot be delivered with any legal certainty.
"For that reason we'll be forced to withdraw our offer today and neither I nor any member of the Blue Knights consortium will be left as the last man standing.''