Caskey's squad has the depth to absorb their injuries, but no more, and the coach will be hoping long-serving team physio Kent Stembridge can work a little magic on the rest in the next couple of days.
Neither starting locks Josh Lane or Jack Hodges trained on Tuesday night with their leg injuries, but Caskey is hopeful they will both come right. Matt Ashworth, Cade Robinson and skipper Campbell Hart are able to step into those spots during matches.
Marist hooker Jack Yarrall, a Wanganui Heartland semi-regular in the past few seasons, comes straight back into the squad, while after just travelling to Napier as a one-off reserve back cover, Kaierau teenager Dillon Adrole stays with the team after he played nearly 60 minutes against Saracens.
"He's a talented kid," said Caskey of Adrole stepping up in tough circumstances.
"We had a few in the casualty ward. We're only going to have two available backs spare.
"We'll go with a 5-2 split on the bench, because we've got no choice."
On a hot day and dried-out field against Saracens, Wanganui got a wake-up call in terms of speed and physicality, therefore work at training this week has been about getting the attacking angles better, so the runners don't get so easily lined up by defenders.
"We're working a fair bit on our ball carry – the channels we carry into, a bit more width," said Caskey.
"Using our skill sets a bit more – we did a bit on Saturday, but it's more about the step up from club rugby.
"Players tend to go into their shell, don't make a pass when they should because they feel someone coming at them.
"It's learning to live a little bit."
Horowhenua-Kapiti started their preseason with a 41-8 hammering from neighbours and Bruce Steel holders Wairarapa Bush - a match that did not count for that trophy as those team's will clash again on October 10.
Therefore, in a two-game series, Wanganui would love to pick up a clear bonus-point win to set themselves for the decisive matchup with Wairarapa Bush, but given his squad's current state, Caskey cannot look that far ahead.
"We'll take it one game at a time and worry about Horowhenua Kapiti well before Wairarapa Bush.
"We start with injuries, so not going to get too carried away."
It will be the first time he has coached Wanganui for a game at the Shannon Domain, which is the home club ground for more than half a dozen of the Horowhenua-Kapiti players likely to front on Saturday.
Coached by Chris Wilton, Horowhenua-Kapiti rebounded from their Wairarapa Bush loss, where they fielded eight debutants, to hammer a Central Hawke's Bay side 59-12 after making adjustments to their lineup.
Captained by the reliable Ryan Shelford, their squad includes NZ Heartland XV regular Willie Paia'aua, who did not play last Saturday, and former Wanganui lock Sonny Woodmass.
"There's a big part of them that have played quite a few games for Horowhenua-Kapiti over the recent 5-6 years," Caskey said.
"There's a fairly settled group, so we know how they play."
Kickoff is at 2.30pm, after a 12.30pm curtain-raiser game of HK Golden Oldies vs Whanganui Bohemians.
Entry is free.
The Wanganui team will be selected from:
Forwards: Wiremu Cottrell, Kamipeli Latu, Gabriel Hakaraia, Hadlee Hay-Horton, Joe Edwards, Jack Yarrall (Marist), Josh Lane, Jack Hodges, Matt Ashworth, Jamie Hughes, Campbell Hart, Cade Robinson, Lennox Shanks, Semi Vodosese.
Backs: Lindsay Horrocks, Cameron Davies, Dane Whale, Craig Clare, Troy Brown, Timoci Seruwalu, Josaia Bogileka, Vereniki Tikoisolomone, Alekesio Vakarorogo, Dillon Adrole (Kaierau).
First Class games – October 3: Horowhenua Kapiti, Shannon (Bruce Steel Memorial Cup round-robin); October 10: King Country, Taumarunui (Sir Colin Meads Memorial Trophy); October 17: Wairarapa Bush, Whanganui (Bruce Steel Memorial Cup round-robin); October 24: Poverty Bay, Napier (Curtain-raiser to Hawke's Bay vs Manawatū).
