All other squad members, other than suspended lock Peter-Travis Hay-Horton, are ready to front and looking to put on a good performance to keep the second spot secure, especially considering the teams just behind them in Thames Valley and North Otago will meet in a pivotal clash in Whitianga.
"They're ok, probably reflecting on Saturday – did enough to win. Excited about getting into this week," said Hamlin.
"We've had fits and starts throughout the season, haven't put on a full 80, as the cliché is.
"We're running out of corners to turn.
"The weather looks like it might be rough again. But we're used to playing on heavy grounds. [Good weather] everywhere but where we are."
Wanting to maintain momentum rather than being strong one minute and back-peddling the next, Hamlin knows discipline will be the key to it – preferring not to have any more members of the infamous 2022 "Card Club".
"Obviously, that seems to be our way.
"I understand the referees and what they're looking at, but they're letting the smallest things go and then jumping all over the others.
"Shift in attitude, and really working hard defensively."
Regarding backline alterations, Hamlin was happy with the first-class debut of the speedy Jack O'Leary on Saturday, who played the last 10 minutes off the bench after Malanicagi was ruled out and Tiari Mumby was unavailable for the game.
"He's fitted in well, that's the idea of the apprentice role.
"It's a matter of if, not when Jack next plays for Whanganui.
"He's got a lot of energy, probably prefer fullback, but he's on the wing.
"He's in the mix, but 3-4 other boys are doing the same."
Buller have been a real mixed bag in 2022, now playing without the erstwhile James Lash, arguably Heartland's greatest ever player, or at least in the debate alongside Whanganui's Peter Rowe.
This season, a 34-29 home win in Westport over Mid Canterbury was followed by a 71-10 smashing from North Otago in Oamaru.
Momentum seemed to be building with a 48-20 home win over Poverty Bay, then lifting the prized Rundle Cup from derby rivals West Coast 36-32 down the road in Greymouth.
However, last weekend they hosted a buzz-saw in Thames Valley, who tuned them up 52-12.
"It's hard to get a read on Buller. You see them one week, they come out with a whiz, then they've taken a couple of decent losses," said Hamlin.
"Got a couple of good forwards – one tall lineout out forward. In games they've won, they've managed to score points."
The coach points out Whanganui cannot get into another "back and forth" style of game, remembering how they led 24-0 early against Buller's neighbours West Coast, and then conceded 19 points in 20 minutes before pulling away in the second half.
Kickoff is 2.30pm on Saturday.
The Whanganui team will be selected from:
Forwards: Keightley Watson, Slade Hay-Horton, Tai Pulemagafa, Ranato Tikoisolomone, Bradley Fountain, Roman Tutauha, Jack Yarrall, Ben Whale, Matt Ashworth, Josh Lane, Mason Johnson, Samu Kubunavanua, Jamie Hughes, Regan Collier, Semi Vodosese.
Backs: Lindsay Horrocks, Caleb Gray, Kahl Elers-Green, Dane Whale (c), Tyler Rogers-Holden, Tiari Mumby, Josaia Bogileka, Timoci Seruwalu, Kameli Kuruyabaki, Alekesio Vakarorogo, Jack O'Leary, Ezra Malo, Ethan Robinson.
