Penrith's Dallin Watene-Zelezniak has been sidelined indefinitely after being hospitalised with a collapsed lung.
The Panthers outside back was admitted to hospital on Tuesday after the onset of a condition that results in the accumulation of air in the space between the lungs and chest cavity.
Watene-Zelezniak has primary spontaneous pneumothorax, a genetic condition that leads to the rupture of small sacs of air in the lungs.
The club does not know if his condition was triggered by a physical blow and his playing future has been put on hold.
It is a massive blow for the Panthers, who are already without regular fullback Matt Moylan (ankle) until round 23.
Watene-Zelezniak has excelled since stepping in to assume the No.1 jumper in Moylan's absence.