However, Slater, whose All Stars spot against the Indigenous All Stars in Brisbane on February 9 will be taken by Storm team-mate Justin O'Neill, is confident of facing the Super League champions at Headingley on Friday 22 February.
"I had a plate out of my collarbone at the end of last year and also rolled my ankle in my first week back at training," Slater told Fox Sports.
"It's kept me off my legs and kept me out of a bit of training over the last couple of months.
"To play to the standard the All Star game requires, you need to have a particular amount of training under your belt and I just don't have that at the moment.
"But I'm pretty confident I will be right to go for the World Club Challenge.
"That will give me a couple extra weeks up my sleeve so I'll be able to get some volume into my running and legs. Hopefully I'll be right for the game."
Slater is following a modified training programme timed at having him near peak condition for the Rhinos clash.
