Manager Justin Lock will be caretaker of the team over the weekend, while its "elder statesman" Dominic Rayner will take over the captaincy.
Regular captain Morgan Inness has returned to university, while English import Greg Smith was injured at training.
Although neither was in form against Wairarapa, their absence does make a brittle top order look even more shaky.
Callum Coker, recently returned to the successful St Johns Tech side, comes into the batting lineup.
The other changes are in the bowling department with both pacers Ryan Slight and Connor O'Leary making expected returns from injury, as Sam O'Leary makes way - as does Josh Trillo, who was a last-minute replacement against Wairarapa - for the returning Bryant Galpin.
"We need a spinner, so we've really replaced [Trillo] with Galpin," said Gillespie.
"Callum for Greg is a straight batter for batter [swap].
It's an opportunity for them to prove themselves, more than anything, that they can play rep cricket," Gillespie added.
This will take a big effort against a dominant Hawke's Bay team who in their cup campaign defeated Horowhenua-Kapiti by 10 wickets, took first-innings points against Wairarapa, accounted for Taranaki by eight wickets and then gained comfortable first-innings points from Manawatu.
Batsmen like Matt Edmondson, who scored 108 against Manawatu, and captain Jacob Smith will look to impose themselves, while spin bowler Angus Schaw has had success against the Wanganui lineup in the past. The home side can hope their four St Johns Tech players - Dominic Lock, Coker, Nick Harding and Ross Kinnerley - are suitably inspired after their Coastal Challenge Cup success on Waitangi Monday.
The Wanganui team is:
Matthew Boswell, Nick Harding, Dominic Lock, Callum Coker, John McIlraith, Hamish Harding, Dominic Rayner (c), Chris Sharrock, Bryant Galpin, Ross Kinnerley, Ryan Slight, Connor O'Leary.