Hull KR winger Craig Hall did not suffer a ruptured testicle in Friday's defeat to St Helens, as first feared.
Hall, 26, was taken to hospital after going off injured at Langtree Park, but subsequent scans have ruled out any rupture, but coach Craig Sandercock says there is no real clear indication as to when he may return to action.
He said: "The good news for Craig (Hall) is that there wasn't a rupture there but he did have to have surgery and the doctor seems to think he'll be out for a reasonable period of time."
Sandercock also has doubts over the fitness of Rhys Lovegrove and Graeme Horne, although expects to welcome back Neville Costigan in to the fold for Friday's trip to Wigan.
Loan signing Ade Gardner, who joined this week on a month's loan from St Helens, is likely to go straight in the squad.
Sandercock added: "Neville was ill and in no fit state to play last weekend but he'll be okay for Friday night. As for Rhys (Lovegrove) and Graeme (Horne), they're touch and go. Their injuries aren't serious, but could be enough to perhaps rule them out for Friday night.
"I'd suggest at this stage that Ade will go straight into the squad on Friday and he's trained really well this week.
"He's just what we needed in terms of his experience and talk out on the pitch and I dare say he'll slot straight in."