Ashworth strengthened the lineout options with Josh Lane's rib injury likely to keep him out for at least the first two games of the competition, while Malo has impressed at fullback and wing with a try and six conversions in the past fortnight.
Stepping out of the squad are loose forward Lennox Shanks, unavailable since the first pre-season game, and veteran first-five Brook Tremayne, whose inner ear issue last week led to vertigo, which was exacerbated by hard contact in the win against Hawke's Bay Saracens.
In the forwards, four players will be looking to make their first-class debuts – flanker Regan Collier and the props Keightley Watson, Slade Hay-Horton and Tai Pulemagafa.
The two fresh faces in the backs will be halfback Caleb Gray and Tiari Mumby, while the three apprentice players Kohlt Coveny, Mason Johnson and Jack O'Leary are in the environment to learn, getting game time only in the case of significant squad gaps.
Hamlin will likely run as close to a shadow Heartland 22-man starting group on Saturday as possible when the tough Wellington Centurions arrive at Cooks Gardens.
Centurions defeated a more settled Whanganui team 19-12 in Porirua last year in the last preseason game before the Covid-19 lockdown meant the start of the Heartland Championship was delayed by several weeks.
Two months later, the same Centurions side beat Whanganui Development XV 99-0 at the Kaierau Country Club.
This season's 30-man team, coached by Kent Harris, is made up of players who were part of the Wellington Lions preseason, and solid veterans from the club scene coming up to help out the predominantly young group.
Last week, in their first game of seven, they smashed the Wairarapa Bush Heartland squad 76-10 in Masterton, after leading 31-5 at halftime.
The home side will hope that after the bout of Covid in his family, leading halfback Lindsay Horrocks should be ready to return to action.
The 2015 Heartland player of the year and current NZ Heartland XV incumbent, Horrocks brings 82 games worth of experience back to Whanganui, now one of less than a handful of players remaining who, since 2014, have been part of three Meads Cup and two Lochore Cup-winning campaigns.
The kickoff against the Centurions is 2.35pm.
The Whanganui squad is:
Forwards: Gabriel Hakaraia (Taihape), Keightley Watson (Marist), Renato Tikiosolomone (Border), Slade Hay-Horton (Taihape), Tai Pulemagafa (Kaiuera), Roman Tutauha (Taihape), Jack Yarrall (Marist), Josh Lane (Kaierau), Peter-Travis Hay-Horton (Taihape), Matt Ashworth (Kaierau), Ben Whale (Taihape), Jamie Hughes (Taihape), Semi Vodosese (Border), Samu Kubunavanua (Ngamatapouri), Regan Collier (Taihape).
Backs: Lindsay Horrocks (Border), Caleb Gray (Kaierau), Kahl Elers-Green (Ruapehu), Dane Whale (Taihape), Ethan Robinson (Kaierau), Josaia Bogileka (Ngamatapouri), Ezra Malo (Hawkes Bay – Player of Origin), Timoci Seruwalu (Ngamatapouri), Kameli Kuruyabaki (Ngamatapouri), Peceli Malanicagi (Ngamatapouri), Alekesio Vakarorogo (Border), Tiari Mumby (Taihape), Tyler Rogers-Holden (Taihape).
Apprentice players: Kohlt Coveny (Kaierau), Mason Johnson (Kaierau), Jack O'Leary (Marist).
