Sonny Bill Williams has been ruled out of the sevens world series tournament in Canada because of a knee injury and is returning to New Zealand.

All Blacks Sevens coach Gordon Tietjens says the injury that Williams has been carrying has flared up and he won’t be risked in Vancouver next weekend.

The 33-Test All Black and two-time World Cup winner was rested from this weekend’s Las Vegas tournament, in which New Zealand have been relegated to the plate competition after losing their quarterfinal to South Africa 14-7.

“He’s got a little bit of an irritable knee,” Tietjens said.

“It sometimes swells up with a little bit of fluid.”

Tietjens said the 30-year-old Williams had the knee drained and it was fine during the week.

“But just after training yesterday, it just wasn’t as good as we would have liked and it swelled up again this morning.”

As with Las Vegas, the Vancouver tournament will be on artificial turf, which Tietjens said would have worked against Williams.

“We therefore thought it was best he return home and get the right treatment and support he needs to speed his recovery.”

Tietjens said Williams would be available for selection for the next two stops on the sevens circuit – Singapore and Hong Kong in April.

Bay of Plenty’s Teddy Stanaway, who made his All Blacks Sevens debut in Cape Town in December, has been called in as replacement for Vancouver.