The newly-promoted side has confirmed Waithira picked a knock during training on Thursday and will thus miss the trip to face the Powermen.
The winger had just recovered from a back problem but during Thursday's session he got a knock which has now ruled him out for about a week.
“Joe [Waithira] is out of our game against Western [Stima],” the club confirmed on their official page.
“He has a slight knock and we have decided to let him rest as he recovers. He should be available for our next game.”
Meanwhile, young keeper Bixente Otieno has been named in the travelling party. He is joined by Dan Owino, Teddy Osok, Musa Masika and Victor Ndinya.
The six were not included in the squad which played Nzoia Sugar a fortnight ago. The big-spending Wazito managed a 1-1 draw against the Sugar Millers in their league opener while Western Stima forced a 2-2 draw against Kariobangi Sharks.
Goalkeepers: Kevin Omondi, Bixente Otieno.
Defenders: Johnstone Omurwa, Bernard Ochieng, Lloyd Wahome, Abouba Sibomana, Karim Nizigiyimana, Dan Owino.
Midfielders: Teddy Osok, Brian Musa, Amos Asembeka, Joshua Nyatini, Ali Abondo, Musa Masika.
Forwards: Victor Ndinya, Paul Acqua, Derrick Onyango, Derrick Otanga, Elvis Rupia.