Super League leaders St Helens’ shock defeat to Salford Red Devils was compounded by injuries to two key players.
Winger Regan Grace pulled up at the end of the game with an apparent leg injury.
Earlier, forward Curtis Sironen had been forced off at the AJ Bell Stadium with a bicep issue.
Both players will require scans to determine the full extent of the injuries.
“Regan went down without anyone touching him and that is usually a bad sign,” said Saints head coach Kristian Woolf.
“Curtis looks like it is similar to Jonny’s (Lomax) injury earlier in the year but we have to get that confirmed.”