Hull FC centre Cameron Scott will be out for at least three months with the ankle injury suffered in their victory over Salford Red Devils last week.
Scott scored two tries in the game but was later forced off and the extent of the injury has now been confirmed by head coach Brett Hodgson.
“Unfortunately, it’s the worst case scenario for Cam,” said Hodgson. “He’s having an operation and best case it looks to be about 12 weeks.
“I’m hugely disappointed for Cam but I’m sure he’ll work hard and get himself back into good shape.”
The Hull boss will also be without any centre, Carlos Tuimavave, for the trip to Castleford Tigers on Sunday.
Tuimavave is yet to feature this season with a hamstring injury and has suffered a further setback.
“Carlos got a little bit of setback at the end of last week when we were preparing for that game,” said Hodgson.
“It looks like he’ll probably be another two weeks, maybe three depending on how he progresses.”
The only positive squad news ahead of FC’s reunion with their former boss Lee Radford is the return from suspension of forwards Andre Savelio and Kane Evans, with the latter in contention to make his debut for the club.