Clarke injured his right hamstring in a test against India in December and underwent immediate surgery to repair it in time for the World Cup.
The 33-year-old was initially expected to return for Australia's second World Cup match against Bangladesh only to see the game washed out by rain.
Clarke said Friday at a pre-match news conference that he's as tired of talking about his personal fitness as he's sure cricket fans are of hearing about it.
Clarke, who suffers from chronic back and hamstring issues, said after his latest injury in December that he feared he may never be able to play again. But after sitting out the past two months, he's back to full fitness and prepared to lead Australia against New Zealand at Eden Park in Auckland on Saturday.
"The confidence I have in my mind and my body at the moment is because of the work I've put in over the last nine weeks so I know I can walk out onto the field tomorrow and go at 100 miles an hour," he said.