Castleford Tigers forward Nathan Massey may need surgery on both his wrists.
Massey, 27, has appeared in all but five of the Tigers' 27 Super League matches so far this season but has been carrying an injury for several weeks.
Centre Jake Webster will also miss the rest of the 2015 campaign after he suffered nerve damage.
"Nathan's having a scan, but he definitely needs an operation - it's a question of whether it's on one or two wrists," said coach Daryl Powell.
"It's an ongoing problem and he's been having painkillers for the last couple of months, but it's got to the point when he's struggling even with painkillers, so the situation needs resolving quickly.
"His other wrist locked up last week and he couldn't tackle anybody."
Castleford, who are fifth in the Super 8s, entertain St Helens on Thursday and need a win to keep their play-off hopes alive.
Forward Andy Lynch said: "It's knock-out football every week. Destiny's in our hands now and we can't rely on the other teams losing - we've got to win all our matches."