All Blacks utility back Israel Dagg feared the worst after rupturing a tendon in his right thigh in May, but now has the chance to force his way into World Cup reckoning.

The 22-year old is expected to be named at fullback for New Zealand in place of veteran Mils Muliaina, who is being rested, in the Test match against South Africa on Saturday.

"When I ruptured the tendon, I thought the dream was over, all my World Cup hopes had ended," Dagg told reporters in Port Elizabeth.

"There were only two case studies on that type of injury in the world, one from America in the NFL and one from Australia in the AFL. Nobody seemed to know what to do, but I just had to have faith in what the medical staff were saying."

Dagg scored the match-winning tries for the All Blacks over the Springboks in both Wellington and Soweto last year and will hope for similar heroic feats to put his hand up to be included in the World Cup squad.

"It's been quite a big travel getting over here but I'm excited to be here and to get the opportunity," he said.

"It's up to me to take it, to put my stake in the ground. The coaches showed faith in me by picking me even though I didn't play the last half of the Super 15; the medical staff had good plans in place, and I need to repay them. It's my only opportunity and I've just got to do it.

"There are always doubts, but you need to get past them. I played a game for Hawke's Bay at the weekend and I kicked the ball as hard as I could and it felt good."