Scans have revealed the full extent of a pectoral injury suffered by Panthers prop Moses Leota in the loss against North Queensland Cowboys in Bathurst.
Leota suffered a partial pectoral tear while making a tackle in the first half of the 26-20 defeat at Carrington Park.
The 22-year-old does not require surgery at this stage but will be sidelined for at least eight weeks.
Leota's replacement in the Panthers side to face Newcastle Knights will be revealed when coach Anthony Griffin names his squad on Tuesday afternoon.
Panthers forwards currently unavailable for selection include Sam McKendry (ACL), Tim Browne (bowel, retired), Corey Waddell (pectoral tear) and Jack Hetherington (suspended), while Trent Merrin is in doubt after undergoing surgery on a dislocated finger.