Widnes will be without Simon Finnigan for the rest of the season after he suffered a serious leg injury against Castleford.
The 30-year-old former Bradford and Huddersfield back rower broke his leg and ruptured ankle ligaments during the Vikings' 36-12 defeat at the PROBIZ Coliseum on Monday.
Finnigan, who is in his second spell with the club, had played in 10 of the club's 13 Stobart Super League matches so far this year.
In a statement issued on Tuesday, Widnes said: "Following a thorough assessment, the Vikings can today confirm that back-row forward Simon Finnigan has suffered a fractured fibula and ruptured medial ankle ligaments following an injury sustained just five minutes into yesterday's fixture at the Probiz Coliseum.
"All at the Vikings wish Simon a speedy recovery."
Finnigan admitted he feared the worst at the time - he becomes the third Widnes player to suffer a serious injury, with half-back Anthony Watts, forward Ben Kavanagh and hooker Thomas Coyle also long-term absentees.
"I realised at the time that it was a bad injury but there's always that faint chance that things may not be as bad as first feared," Finnigan said.
"Unfortunately, it's turned out to be the worst case scenario and I'm absolutely gutted."
News of the injury to their former skipper is another body blow for the struggling Vikings, who announced on Monday night that Watts would be returning home early to Australia just weeks after signing a new contract.
Denis Betts' side have won just twice so far on their return to the top flight and currently sit bottom of the table.