Hardaker, 21, suffered a fracture to his thumb in last Friday’s win at Salford, which will see him out of action for up to six weeks.
Prop Bailey is recovering from a minor operation on his knee, and will be out for three weeks.
Head Coach Brian McDermott said: “It is disappointing for Zak, especially to miss out on the World Club Challenge. We have got a few options that we are looking at for full back against Melbourne and we will make some decisions over the next 48 hours.
“Ryan Bailey has put his hand up this week but he only had the operation last week and he has to allow his wounds to heal.”
Both Hardaker and Bailey played in last year’s 26-12 World Club Challenge win over Manly.