Castleford Tigers forward Craig Huby has been ruled out for at least four months after fracturing his knee.
The 24-year-old prop underwent an operation on Tuesday night after suffering the injury in the 22-20 Easter Monday defeat at St Helens.
"He was operated on last night and it went well," said coach Terry Matterson.
"He's going to be out for months. I'd say four minimum. Fingers crossed we can get him back for the semi-finals."
Huby has been playing some of the best rugby of his career to help take Cas top of the table in their best-ever start to a Super League campaign.
Matterson is convinced that the injury has denied Huby the chance to represent his country against the Exiles on 10 June.
"He was in with a real chance of making the England squad," said Matterson.
"He and James Graham have been the best two front-rowers this year. I don't think there would be any argument about that.
"He's been getting better and better. He's worked hard over the years to get to this stage but he's become mentally strong and he'll be fine.
"We're going to miss him but we've got to deal with these things."
Huby is the Tigers' third front row forward to go down with an injury, having already lost Jonny Walker and veteran Nick Fozzard this season.