Newcastle's David Klemmer is expected to miss the next four to six weeks after fracturing his wrist in the Blues' loss to Queensland on Wednesday night.
The 25-year old is awaiting the results of scans from Thursday night to determine the severity of the issue, but has already been ruled out of the next two Origin games.
Knights CEO Phil Gardner said it was a major blow for the club.
"We are all shattered for him," Gardner told the Newcastle Herald.
"He has been simply outstanding for us this season and he showed his courage by playing with it without knowing on Wednesday night against the Maroons.
"From the club's point of view, it's extremely disappointing but it's a tough game and unfortunately, these things happen."
Klemmer has been massive for the revitalised Knights this season, currently sitting fourth on the ladder with six wins and five losses.
He played the opening 51 minutes of the Origin opener before mysteriously sitting out the rest of the match.
The loss of the star prop is a major blow to the Knights' finals hopes, averaging 176 meters and 35 tackles per game.
Pasami Saulo will replace him for Newcastle's clash with South Sydney on Friday night.
Massive loss for the Knights and NSW
Do we call in RCG and M’Clean?