Penrith prop Sam McKendry has gone under the knife for his second knee reconstruction in less than a year.
The 27-year-old Kiwi international injured his knee in a trial match against Parramatta in February - his first game back since rupturing his ACL last July.
Panthers coach Anthony Griffin said the club tried to avoid surgery but were left with no option but to send him to hospital last Thursday.
"We went down the track of trying to rehabilitate him but it got to a point where it wasn't going to work," Griffin said after Penrith's 28-6 loss to Melbourne at AAMI Park on Saturday.
In some more positive news for the Panthers, young Rawene forward James Fisher-Harris is likely to return from a fractured cheekbone for next Friday night's clash with South Sydney.