Warriors captain Roger Tuivasa-Sheck celebrates with teammates.

Stephen Kearney expects Warriors fullback Roger Tuivasa-Sheck to flick the switch and get back to his running best against St George Illawarra on Saturday.

Tuivasa-Sheck has been particularly quiet over the past fortnight as the Warriors have slipped to eighth on the back of four losses in their past five matches.

He coughed up several unforced errors in a gritty 12-6 loss to the visiting Storm and then suffered some of his own twinkled toed medicine in a 36-12 mauling from Gold Coast last Sunday when Titans winger Phillip Sami left him floundering with an RTS-esque step for the first of his two second-half tries.

Kearney has gone into bat for his embattled skipper leading into Saturday's round-21 clash at WIN Stadium, wondering out loud if the birth of Tuivasa-Sheck's daughter in early June and the resulting sleepness nights hadn't blunted the star stepper.

"It's been a big change for him to be honest over the course of the last month or so, he's living with a young child in the house now," Kearney said.

"And he's a captain of a team that's in a position to jump into the finals potentially for the first time in whatever (seven) years, so there's probably been a fair bit go on for Rog too. So my advice to Rog is just to simplify it for himself and go out and focus on what he does best.

"He sets such real high standards for himself that he's disappointed when he's an eight out of 10 and not a nine, that's why he's the type of player that he is."

For Kearney, the recipe is simple for the skipper if not easily achieved in the cut-throat run into the playoffs against equally desperate opposition.

The 25-year-old has averaged 171 running metres in 17 appearances but has watched over five losses in the eight matches since the arrival of his daughter and was off-colour against the Titans with 160 metres, a solitary offload and two missed tackles.

"I expect Roger to respond how I think everyone would expect Roger to respond and that's by getting back to what Roger does best. I think the best asset he has is his running game," Kearney continued.

"I want Roger to take opportunities but again it's about getting the balance right and that's a delicate line. Again, how many times has he held onto the ball and got in behind the defence, then done whatever Roger does and had a positive result for us?

"That's a constant work on to get the balance of that, a guy in his position, to get the balance right between the passing and the running and setting the outside men up effectively or taking the space yourself. So that's the processes we're continually working on with the likes of Rog.

"When you see Roger running well and taking the line on first, we know that he's in a real good head space."

One area where Kearney won't hear any criticism of his fullback is the young playmaker's captaincy.

"I think it's a bit unfair to look at the last two weeks... looking at his own [sub-par] performance. But in terms of his leadership, he's second to none. I think he's done a wonderful job [this season]," Kearney said.

"He leads from the front, is first to bounce out onto the training pitch, so what I'm saying is, Roger's captaincy is wonderful. He's got a really good bunch of leaders around him and all of them, between them, have done a great job this year and we're really determined to make sure we finish off the year the best we can."