Zak Hardaker is facing a battle to be fit for Leeds Rhinos' World Club Challenge clash against Melbourne after suffering a thumb injury last night.

The full-back sustained the knock during the first half of 42-14 Super League win over Salford City Reds - a game he only started after passing tests following a blow to the head against Castleford Tigers last weekend.

Coach Brian McDermott confirmed he does not expect Hardaker to make next week's fixture, suggesting the former Featherstone man could be out for six weeks, and also ruled Ryan Bailey out of the game after knee surgery.

He does expect veteran forward Jamie Peacock and the versatile Brett Delaney to return, though, and also gave Joe Vickery a fighting chance of playing ahead of schedule.

"He (Hardaker) had a bang to the thumb. He needs an x-ray and that's not looking good," said McDermott.

"He will have his x-ray over the weekend but he can't use his thumb at the moment. I'm a realist and at this stage it's not looking good.

"We have a few options at full-back. We will have a look at some stuff, but Kallum Watkins is a likely option at this stage."