Ben Flower could be out for up to eight weeks with a back injury sustained on Sunday.
He left the 19-18 win at Hull KR early and was taken to hospital for scans amid fears he had damaged a vertebrae.
While he was cleared of major injury, Adrian Lam has revealed he doesn't expect him to be playing soon.
"Ben could be out for up to eight weeks depending on how he responds," he said.
"He's got bruising and they're saying four to eight weeks but it's week to week, depending on the pain levels."
Flower is the third prop from the squad which started the year to be ruled out. Gabe Hamlin is suspended following a UK Anti-Doping violation - his case has yet to be concluded - while Taulima Tautai has been stood down while the club investigates his drink-driving charge yesterday.
Romain Navarrete and academy-products Ollie Partington and Liam Byrne are in Lam's squad.
Meanwhile, he hopes to have Joe Greenwood (ribs) and Zak Hardaker (hamstring) back for next week's match at Huddersfield.