Fellow Lion Dan Lydiate also faces a battle against time to regain his fitness for the first Test against the Springboks on June 14.
But No.8 Faletau, who was a starter in the third and decisive Test against the Qantas Wallabies, believes a new guard containing Josh Turnbull, Aaron Shingler and Dan Baker will all step up.
"The back rowers we have got are quality enough to fill in for whoever is missing," he said.
"They know what the challenges are ahead of us.
And Faletau intends to go blow-for-blow with a physical Springboks side on his first visit to South Africa.
"It will be my first time out there and South Africa will test everyone," he added. "They are one of the most physical sides out there. That's how they play - straight up.
"There is no secret about how they play or what they will do. They are very physical men.
"We just have to carry the ball - be hard and direct against them."