Waterhouse, 29, suffered an injury to his pectoral muscle in the Panthers’ 24-22 home defeat at the hands of Canberra on Saturday.
Depending on the severity of the damage, Waterhouse could face surgery and a lengthy rehabiliation period of up to six months.
The news is another huge blow for the club ahead of their must-win clash with the Roosters after Frank Pritchard limped off early in the game with a hamstring problem.
Pritchard will undergo an MRI scan to investigate the problem, but it is unlikely he will have any involvement at the weekend.
Meanwhile, Tim Grant has re-injured the ankle that saw him miss football some weeks ago but the injury is unrelated the syndesmosis he had previously.
This time round it appears as though he may have damaged some lateral ligaments but it is not known whether this injury will keep him out of next weeks game.
Luke Lewis is continuing to have problems with his calf muscle and has picked up a minor shoulder complaint. Neither injury is expected to see him sidelined.