New Zealand lock Keith Robinson has been ruled out of Saturday's World Cup opener against Italy with a calf strain.

The injury-prone 30-year-old will be rested from the Azzurri clash, having fought back from career-threatening knee and back injuries to join the 30-man squad.

"It's not ideal but you have to play the cards you've been dealt and get on with the job," said Robinson.

"I've given it a little tweak, I'm managing it and we're taking it 24 hours at a time."

Coach Graham Henry added: "He is getting the best treatment available and has a very positive attitude. We're hoping he will be ready in a couple of weeks."

Henry must now risk one or both of first-choice second rowers, Chris Jack and Ali Williams, against the RBS 6 Nations side.

Versatile veteran Reuben Thorne may also move into contention.