The versatility of Cowan and Rabo means one of them will probably slot into midfield should Spierling be ruled out and Paul Ryder, who had a quiet first half against Tawa, will start at striker.
Last Saturday's match was the debut appearance of Fijian international Esava Naqeleca for Wairarapa United and with Waisake Sabatu and Miroslav Tvaroh made a favourable impression with his solid defence.
Naqeleca is also capable of filling a midfield slot and Keinzley said he would be experimenting with him there at training this week. "It's another option we need to look at. The more we have, the better."
The form book says Wairarapa United should have the edge on Wellington United but Keinzley is aware of the latter's impressive showings.
"It's just another of those games where if we play well, we will very likely get the result we want but if we don't, we will just as likely be in trouble," he said. "They certainly won't roll over for us, we know that."