Kikau arrived at the rebuilding Bulldogs to considerable fanfare in the off-season but suffered his long-term injury at training only four games into his four-year contract.
The Fijian international has been sidelined since mid-April, though had been considered a chance to return in time to face the Panthers, where he played 123 games including the 2021 and 2022 grand finals victories.
But Kikau fell at the last hurdle, unable to clear strength and contact training drills at Canterbury's final training session on Saturday morning.
He was omitted from Cameron Ciraldo's game-day squad along with State of Origin winger Josh Addo-Carr, whose hamstring injury will sideline him for at least another week.
Ciraldo was the architect of Penrith's dual premiership-winning defence prior to arriving at the Bulldogs for his first head-coaching job this season.
But the Panthers' system has not yet worked for Canterbury, who have conceded more points this season than any other side and came into the weekend in 14th place on the ladder.
The Bulldogs have leaked 190 points across their last four games, only 28 fewer than Penrith have conceded all season.
Canterbury have found it particularly difficult to stop tries from close range and in the middle of the park, areas that were again cause for concern in last week's 44-24 loss to an understrength Brisbane.
They cannot afford a repeat when they meet the Panthers, who welcome back their Origin players and Nathan Cleary and whose middle forwards are among the most ruthless in the competition.
But Ciraldo is prepared to remain patient with his young side and will not turn up the volume to get his message across.
"Spraying people isn't going to help our situation right now," he said.
"It's about trying to help our team become better, about trying to help individuals become better every day.
"With that sometimes it does get frustrating but if you put yourself in their shoes, what do they need to get better and what does our team need to get better?
"A lot of the time spraying is not going to help."
Ciraldo was confident the Bulldogs would eventually take to the defensive tools and tricks he administered at Penrith.
"This weekend, it's system against system," he said.
"It's the same system but there's a group there that's been doing it longer and has learned to love defence.
"That's where our group needs to get to, they need to learn to love defence. Once they get that, those sorts of system errors take care of themselves. We're on a journey to get to that point."
