Calf injury rules Handre Pollard out of Rugby Championship

South Africa out-half Handre Pollard will miss the Rugby Championship with a calf injury as director of rugby Rassie Erasmus concedes the loss of his first choice number 10 was a "worry" ahead of the World Cup in France.

The defending champions will be Pool B rivals of Ireland at the World Cup later this year, with the pair meeting at Stade de France on Saturday 23 September.

Pollard was instrumental for the Springboks when they were crowned world champions for the third time in Japan four years ago and his absence for their title defence would be a heavy blow.

Erasmus is hopeful Pollard will return for warm-up fixtures against Wales and New Zealand in August.

"Handre is a bit of a worry," Erasmus told reporters on Tuesday.

"It's a tricky situation because it's a calf injury that he's re-injured. A re-injury always has us a bit more nervous."

Better news for the Boks is the return to fitness of versatile back Damian Willemse, who can cover out-half, centre and full-back.

Manie Libbok and Elton Jantjies are the other two in the squad who can play at 10, but all three lack the precise boot of Pollard and are better with the ball in hand, which does not necessarily suit the Boks' style.

Pollard will sit out the Rugby Championship along with captain Siya Kolisi, who is recovering from a knee injury.

"We want Handre to recover fully because you don't want to push him too early," Erasmus said. "His timeframe is now like Siya's, we're hoping they both return either against Argentina in South America or the Wales and New Zealand (World Cup) warm-ups."

The Boks are preparing for their Rugby Championship opener against Australia in Pretoria on July 8.