Queensland coach Mal Meninga must hope Billy Slater is fit to take his place in State of Origin I, because former Blues great Brad Fittler says NSW will find it tough to shut him down.

Slater is currently batting a shoulder injury, the same niggle that saw him miss the Anzac Test against New Zealand earlier this month.

"It's very hard to mark up on Billy because he turns up in the middle, on an edge, chasing a kick – he's just everywhere," Blues assistant coach Fittler told SportsFan.

"It's so hard to defend, it must just be a nightmare. His fitness levels are just off the Richter.

"Even when you do your job on Greg Inglis and Sam Thaiday, and you do your job on Corey Parker's offloads and Johnathan Thurston, Billy Slater just pops up somewhere where you didn't think he was coming (from)."

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