"I wouldn't be in this situation if I didn't think I was [going to be fit] for Sunday, it's all going well so far," Slater told media on Wednesday.
"I understand what it takes to play a game in an Origin, I'm pretty confident I'll be right on Sunday."
Slater is set to play his 30th State of Origin match when Queensland face New South Wales on Sunday with the Blues looking to lock up a series win at home following a 22-12 victory in Melbourne in game one.
"We've got a challenge in front of us, we've got to go down to Sydney, it won't be easy," he said.
"We definitely think we can improve on our performance and I'm looking forward to the challenge."
Slater's likely successor at fullback, Newcastle Knights star Kalyn Ponga, has joined the Queensland squad as the Maroons' bench utility for game two and Slater said he'd be happy to allow Ponga to play at the back if coach Kevin Walters' game plan warranted it.
"I think Kalyn is going to play multiple positions, fullback could possibly be one of them, I'm not too sure but he's an exciting player and I'm sure he'll do a great job," he said.
"I'd be happy to move around, I'll do what's best for the team."
"I'm sure Kevvie's got a plan in his head. I haven't spoken to Kev about his plans with Kalyn just yet but he's certainly going to be a great attribute coming on the field for us when the Blues are a little bit tired."