Scans have revealed the full extent of the knee injury suffered by Panthers forward Viliame Kikau against South Sydney on Saturday.
The 23-year-old will be sidelined for up to six weeks after suffering a Grade II medial ligament injury to his right knee.
"He (Kikau) will rehab strongly and come back better than ever," Panthers Executive General Manager Phil Gould AM said on Twitter.
Kikau's immediate replacement in the Panthers line-up will be confirmed on Tuesday when coach Ivan Cleary names his side for the upcoming trial game against Parramatta.
The match will be livestreamed on penrithpanthers.com.au, with commentary from Phil Gould and Mat Thompson.