The player sustained the injury in the Wildcats’ heavy defeat to Widnes at the weekend.
“It’s medial knee ligament and maybe cartilage damage as well,” Webster told BBC Radio Leeds.
“It’s at least eight, but could be 12 weeks. We’re waiting for scan results.
“If I’m honest I doubt we’ll get anyone in on loan. With all the fixtures over Easter, teams want to keep hold of their players.”