Some English Football League clubs will struggle to stay afloat beyond Christmas if there is a delay to the wider return of fans and a financial rescue package is not secured urgently, BBC Sport has been told.
The ongoing absence of fans inside grounds - beyond selected pilots taking place this weekend - means EFL clubs are estimated to be collectively losing more than £20m a month.
Discussions are taking place about what assistance the Premier League might provide, with a request having been lodged for around £200m.
Top-flight club owners are thought to have asked for assurances on how the money would be spent, given concerns over it fuelling wage inflation or being used on transfers.
The BBC has been told that if money does not start coming in within weeks, either from crowds or financial assistance, then some clubs face an uncertain future.
Some sports are bracing themselves for the possibility of the 1 October target being pushed back by a month, given the recent uptick in coronavirus infection rates and concerns over the increased use of the transport network and the public perception of allowing crowds.
However, the timings were not discussed at a meeting between major sports and culture secretary Oliver Dowden on Wednesday, which was described as "constructive and productive".
Instead, the sports were given an opportunity to discuss the "serious financial situation" they are facing, and the implications if fans cannot return soon.
Currently, pilots are capped at maximum 1,000 capacity, and are not permitted in areas where local lockdowns are in place.
Meanwhile, the government is reviewing its plans relating to the return of fans next month and has said it will complete this "rapidly".
A joint statement issued by the governing bodies for football, tennis, horse racing, cricket, rugby league and rugby union said: "We conveyed to the secretary of state the very serious financial situation now facing our sports, clubs and venues and that we believe we can stage events safely.
"It is clear that if fans cannot return soon that there will be very serious economic implications across our sporting sector.
"Our sports have already demonstrated through staging fixtures behind closed doors, in test events and through the return of recreational sport that we can deliver the very highest standards in safety and best practice.
"We will continue to engage with the government in the days ahead and provide any further evidence required.
"It is our firm belief that sports fans will be as safe as in other areas of activity currently permitted."
On Wednesday, Daniel Gidney, chief executive of Lancashire County Cricket Club, told BBC Sport: "After the World Cup and Ashes last year, those were big events and it was difficult to top that but in many ways this year has been more challenging and complicated.
"We normally do two to six days of international cricket and we've done 21. I'm incredibly proud, this is history-making."
Asked what would have happened if matches hadn't been played, Gidney said: "When Tom [Harrison, ECB chief executive] was in front of the DCMS Committee, he said it would be a £300m hit to the game and those figures do not lie.
"Without the broadcast games going ahead we were looking at £200m of broadcasting revenues were going to be at risk so what that means is all 18 counties would not be able to get the distribution numbers from the governing body which could've easily meant some counties had gone bust. This would have been a number of jobs and institutions lost to the game."