Kolisi was sidelined in April while playing for the Durban-based Sharks and early predictions were that he would struggle to be fit for the defence of the Boks’ title having been a central figure when they lifted the Webb Ellis trophy in Japan four years ago.
But the loose-forward will get a first run against the Welsh, and possibly New Zealand at Twickenham on August 25th in a bid to prove his fitness before the Boks take on Scotland in a vital Pool B opener in Marseille on September 10th.
With several leading players having already been ruled out of the World Cup through injury, he is taking a philosophical view.
"You always have that small doubt, but I can’t think about that," Kolisi told reporters on Friday.
"Whatever happens tomorrow, I have peace in my heart that I gave myself the best chance to be here.
"If it (fresh injury) happens, it happens. I am not walking in fear, I am walking in confidence because I feel good."
Kolisi has been chomping at the bit on the sidelines and says he will not hold anything back at the Principality Stadium.
"The coaches have said I must give everything I can for as long as I can until they take me off. Whether that is in the first half or at half-time, or afterwards, we will see how long I can last," he added.
"My role doesn’t change, I am going to play as hard as I can for as long as I can."
Despite his injury, Kolisi has been part of the squad for the entire year, even travelling with the team to New Zealand during the Rugby Championship.
He says they are well aware of their shortcomings ahead of the World Cup.
"I know where the team is and I believe our best is yet to come," he said.
"We have used 48 players in the last 10 games as the coaches gave everyone a chance, but now the World Cup squad has been selected, we can work on our combinations. We know where we can improve."
