England fly-half George Ford could be set for a spell on the sidelines after suffering a torn thigh muscle during Sale's 45-26 Gallagher Premiership defeat to Saracens.
Ford underwent a scan on Monday evening after being forced off inside seven minutes of Saturday's game at StoneX Stadium.
Sharks director of rugby Alex Sanderson is awaiting a full diagnosis to determine how long the playmaker will be sidelined.
England begin their four autumn internationals on Saturday, November 2 when New Zealand visit Twickenham.
"Just the initial reports from the scan, it is a tear," said Sanderson. "It was definitely the right thing to bring him off.
"We don't know the length of time that will take to rehab at this point. We haven't got anything definite or concrete to tell you now.
"He's important to us, King and country. Nationally important, he is.
"I can perceive (him) being back (after) not an overly-long layoff given how he walked off the field but that's the only subjective analysis I've got on it."
Ford missed his country's summer tour of Japan and New Zealand with a damaged Achilles.
He left the pitch against Sarries soon after attempting a long-range penalty.
The 31-year-old, whose existing Sale contract expires at the end of the season, is in talks over extending his deal to the 2027 Rugby World Cup, with Sanderson confident of reaching an agreement.
"It's up for renewal at Christmas and we are in negotiation for extending to the World Cup – positive tones, I might add," said Sanderson.
Sale, who host Gloucester on Friday evening, remain uncertain when England lock Jonny Hill will be back in contention for selection.
Hill is still awaiting the outcome of a police investigation sparked by his reported altercation with a Bath fan in June.
"We have no clarity on Jonny with regards to the exact date he's going to return because it's still with the authorities at the moment," said Sanderson.
"I have to take deep breaths and accept that it's out of my control and out of Jonny's at this moment in time.
"It's not like we're not chasing it up. We've got barristers on the case and have had since the start of this. It's just a long process that is not conducive to professional sport."
