Salford full-back Niall Evalds suffered a broken leg in their defeat to Huddersfield last time out.
The 24-year-old has impressed for the Red Devils this season, scoring seven tries in 15 appearances in 2018.
No timescale has yet been given for his return, but he is likely to miss England Knights’ tour of Papua New Guinea in autumn.
Salford coach Ian Watson is disappointed to lose Evalds.
He said: “Losing Niall is a massive blow for us.
“He’s been terrific so far this season in attack and defensively with his backfield play.
“However, I’m confident with the players that I have at my disposal that we can adjust and continue to perform while Niall is sidelined.
“This creates a chance for other players in the squad to now step in and grasp their opportunity with both hands.”
The Red Devils have a couple of options to choose from in terms of filling in at full-back. Derrell Olpherts, Greg Johnson and Jake Bibby could all fill the void.