Warrington hooker Michael Monaghan may be out for five weeks, while scrum-half Richie Myler could miss three weeks.
Monaghan, 34, has a calf injury and Myler, 24, requires an ankle operation.
Head coach Tony Smith told BBC Radio Manchester: "Richie has got a little bit of floating bone in his ankle so hopefully just a tidy up and nothing too much more sinister than that.
"Mike has got a tear in his calf muscle but it's probably not as bad as first feared. We think four or five weeks."
Smith added: "We thought he (Monaghan) was going to be out seven or eight weeks but we should be getting him back sooner.
"He (Myler) will hopefully be a two-to-three week recovery."