The twice World Cup-winner took part in a training camp in Cambridge, New Zealand this week ahead of the third leg of the Sevens World Series in Wellington at the end of January, where he is expected to be selected for the first time.
Williams has enjoyed success in rugby union, rugby league and was New Zealand's heavyweight boxing champion but switched to Sevens with an eye on winning a gold medal when the sport returns to the Olympic fold in Rio de Janeiro later this year.
The 30-year-old spent the week in the training camp trying to learn the ropes from his team mates as well as improve his fitness to match the much higher demands of the shorter version of the game.
“The first day we got in we did a beep test. Usually, in our (Rugby Union Super Rugby) franchises, we do a beep test but there's not too much after that,” Williams was quoted as saying by New Zealand media on Wednesday.
“But then we came out here for what I think was about an hour of fitness games, and after 20 minutes I couldn't get out of a jogging pace.
“It was a bit of a wake-up call but in saying that, I know where I'm at and I know where I want to go. I know that comes from a lot of hard work and I'm just lucky enough to be given the opportunity to be around these guys 24-seven.”
New Zealand head coach Gordon Tietjens has overseen 12 titles in 16 years of the Sevens World Series, working with the rugby-obsessed country's finest names, including Jonah Lomu and Christian Cullen.
Tietjens said he had been impressed with Williams' work ethic and that the code-hopper had settled in well with the squad, who struggled in the opening legs of the Sevens series in Dubai and Cape Town.
“He's so professional and he's very infectious. I mean, the players just follow him and learn from him,” the trophy-laden coach said. “There's so much you can learn from Sonny Bill Williams and the professional footballer he is.
“He is a superstar, but he knows he's got to work as hard as anyone to make this side.”
Tietjens, whose side finished a surprise third behind Fiji and South Africa in the Series last year, said it was important not to rush Williams into action.
“He's really nervous, he wants to grasp the information and when it's time to put him out I certainly will do that,” the coach said.
“He certainly could be in Wellington, and more than likely will be in Wellington, but we want to be confident that he's going out... right and ready to go.” – Reuters
Original source: Sonny Bill nervous ahead of Sevens debut