Worcester boss Steve Diamond says it would be a "remarkable feat" if the owners secure new investment in time to save the financially stricken club.
Warriors owners Jason Whittingham and Colin Goldring said terms of sale for the Premiership club had been agreed with an investor on Tuesday.
But the club said on Wednesday evening they are still awaiting "final sign-off" on the contract for the sale.
Warriors are scheduled to play their first home Premiership game on Sunday.
After weeks of uncertainty surrounding the club's future since HMRC issued a winding-up petition over an unpaid tax bill of £6m and late payments to players and staff, Warriors began the new Premiership campaign with a 45-14 defeat at London Irish on Saturday.
Mystery still surrounds the identity of the club's potential new investor, and whether they would become the new owners or just a stakeholder.
Whittingham and Goldring said the deal would ensure an immediate injection of cash that would enable Sunday's game against Exeter to go ahead.
But that is yet to be made official.
"Let's hope this is not another false dawn. These people have to deliver and I think they're in the last throws of that," Diamond told BBC Hereford and Worcester.
"It's better to have a potential deal on the cards than not but if it's another cock-and-bull story, it'll be out in the wash at the weekend because we won't be playing.
"I don't think they're [Whittingham and Goldring] spinning a yarn. I think they've genuinely got somebody."
'Frustrating delay'
Diamond added that he "has no real details" about who the potential new investors are - only that they are "rugby fans" and has been told confirmation of the deal is "imminent".
"Not steering the club towards administration is a really good factor on behalf of the current owners - there are so many ramifications.
"To say that and then go and pull a rabbit out of a hat and find an investor is another remarkable feat."
Worcester released a statement later on Wednesday to say they are still awaiting "final sign-off of the heads of term on the agreement of the sale of the club to a buyer".
The club said the agreement "remains with the lawyers of the respective parties but signing of the heads of terms is required before the sale can be concluded".
It is working with Premiership Rugby, the Rugby Football Union and Department for Digital, Culture, Media and Sport to ensure this weekend's scheduled fixtures - including their Premiership match against Exeter and the Allianz Cup tie between the University of Worcester Warriors and Harlequins Women - can go ahead at Sixways.
"We appreciate that the delay is frustrating for our loyal staff, sponsors and supporters and we thank them for their continued patience in these challenging circumstances," the statement added.