Cowan is a definite non-starter because of a work commitment in Fiji while Higham is "very doubtful" because of health-related issues.
They both play on the outside of the midfield and, if Tuesday's training session is any indication, the likelihood is that usual fullbacks James Oxtoby and Pablo Moya will move into those slots.
Neither of them have the pace or natural flair of Cowan and Higham but they are good tradesmen with a positive attitude and Keinzley is confident of them doing a decent job if that's the way the selection process goes.
"We would be down in pace, no doubt about that, but the resolve will still be there, and that always counts for plenty," he said.
Keinzley said Wairarapa United would still be looking to play their usual brand of attacking football with the inventiveness of Seule Soromon and Paul Ryder up front being their main weapon.
"The busier we can keep them the better for us," he said.
Napier City Rovers, for their part, has been strengthened by the acquisition of former All White Cole Peverley who will boost their already impressive attacking strength and the Wairarapa United defence will need to be right on their mettle to keep them at bay.
And to that end the onus will be on the likes of Tim Schaeffers, Waisake Sabatu, skipper Nathan Cooksley and Carl Shailer to give goalkeeper Phil Imray adequate protection.
"Defensively we have to work as a unit otherwise they will punish us, they are good enough to do that," Keinzley said.
