Tapine's wife went into labour on Friday morning and the 28-year-old New Zealander will remain with her in Canberra for the birth of his first child.
He joins a growing list of absentees including Jack Wighton, Xavier Savage and Nick Cotric, meaning the 1-4 Raiders will try to snap out of their form slump without arguably their best middle, half, fullback and outside back.
Earlier on Friday, Canberra coach Ricky Stuart admitted the Raiders' confidence had taken a serious knock in their 53-12 mauling at home to the Panthers in round five, but implored his players to leave that defeat in the rear-view mirror as they head to Suncorp Stadium.
Injuries and suspensions have meant only minor personnel changes, with young centre Harley Smith-Shields replaced by returning veteran Jarrod Croker and powerhouse forward Corey Horsburgh joining the starting unit at lock.
Young prop Peter Hola is poised for his Canberra debut after joining the side in Tapine's absence.
Stuart said the disappointment had been palpable when the Raiders returned to training after their Penrith pummelling.
"It's not the football team we are," he said. "We're a better football team.
"I made sure we picked up our bottom lip Monday and got on with the job. There's no time to look back.
"We're going to look forward ... they're certainly working hard towards our next game. That's all I can ask."
Canberra's much-maligned second-half record came to the fore against the Panthers through a 40-6 scoreline, with a 24-0 Penrith blitz in the last 20 minutes an uncomfortable reminder of the ACT club's 'Canberra Faders' tag.
The numbers don't make for pretty reading: Canberra completed at 57 per cent, were out-gained by 541 metres and missed 34 tackles as the Panthers piled on the points.
"It's simple ... we need to stop making errors," Stuart said.
"I can't crucify a team for individual error.
"It's not mentality, it's not what's being said or what we're doing at halftime.
"Take ownership and responsibility for your own performance, it's as simple as that.
"Every individual coach, player has to get their game right."
Horsburgh starts in place of struggling Corey Harawira-Naera, the second-rower running for just 40m in his last two games combined.
"We need to win a game of football, so I've got to keep trying to find a combination of winners," Stuart said.
"Everybody knows there's been injuries, there's been suspensions all year, but nobody wants to hear excuses.
"People want to see you trying to find a combination to win a game of football and that's what we're trying to do."
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