Premiership Rugby is conducting an "urgent review" ahead of Sunday's final round of regular-season fixtures after 16 Sale players tested positive for coronavirus.
Sale indicated on Friday their crunch clash against Worcester would go ahead as the Sharks look to avoid forfeiting the game - which would result in a 20-0 defeat and potentially jeopardise their hopes of a top-four finish.
But league chiefs revealed the entire weekend program is now under review following the outbreak at Sale, while the governing body says it has been made aware of positive tests at other clubs.
Those results will be analysed and may act as a determining factor in deciding whether any of the matches can proceed as planned.
Darren Childs, chief executive of Premiership Rugby, said: "The health and well-being of our players and staff is our priority.
"More than 900 PCR COVID-19 screening tests were carried out on Thursday. On Friday we received the results, which was followed by a comprehensive contact tracing program at our clubs, created by those positive tests.
"These results are being analysed with the help of Public Health England and the local health authorities involved. This will allow a decision to be made over the Sale Sharks v Worcester Warriors match, and any others that have been affected by positive results.
"We understand the stakes are very high this weekend but we have a responsibility to everyone involved with Premiership Rugby to ensure a methodical process is followed, and this cannot be rushed."
Childs' comments in a Premiership Rugby statement came just an hour before the teams were due to be announced on Saturday.