Coach Sir Gordon Tietjens said in a statement he had chosen to rest Williams, following "pleasing" performances at tournaments in Wellington and Sydney, both won by New Zealand.
Tietjens also left out experienced back Sherwin Stowers when reducing his 14-strong travelling squad to 12 ahead of the three-day tournament starting on Friday.
Speedsters Sione Molia and Josh van Lieshout will both make their world series debut, having shone for the victorious Counties Manukau at the sevens national championships.
Tietjens has also handed a recall to Liam Messam who, like his Chiefs and All Blacks team-mate Williams, has ditched any 15-a-side aspirations this year to pursue sevens selection for the Rio Olympics.
Meanwhile, The New Zealand sevens team are bracing for a fast and furious tournament in Las Vegas with the latest stop of the world series being played on an artificial surface.
The Sam Boyd Stadium in Las Vegas features an astroturf field and Tietjens believes it will have an impact.
Next week's tournament in Vancouver will also be played on an artificial surface.
"It will mean heavy legs and grazes," Tietjens said.
"But it will be a firm surface and the teams that adjust to it will certainly play well in this tournament.
"Canada train on it all the time, they will certainly come into the tournament with a huge advantage."
New Zealand are looking to continue their revival in the series. Wins in Wellington and Sydney at the last two stops of the 10-tournament season have lifted them to equal first on the points table with Fiji and South Africa.
Tietjens says the squad have settled into their new surroundings.
"We have travelled and trained pretty well," he said.
"Some new guys coming into the squad have made it a bit of challenge but it's coming together. The guys are starting to gell.
"It's been a while since Sydney but we trained well in camp before we came here and now it's more about tactical and technical things."
New Zealand played a training game against Germany that left Tietjens reasonably satisfied.
This tournament replicates the format for sevens' introduction to the Olympics with teams playing two games a day over three days.
New Zealand face pool matches against Portugal, Russia and Kenya.
Quade Cooper (Australia) and Bryan Habana (South Africa) are the latest 15s stars to try their hand at sevens with an eye to making the Olympics.
New Zealand haven't won the United States leg since 2008. Fiji are the defending champions.
Squad: Tim Mikkelson (capt), Kurt Baker, Dylan Collier, Sam Dickson, DJ Forbes, Gillies Kaka, Josh Van Lieshout, Liam Messam, Sione Molia, Lewis Ormond, Beaudein Waaka, Regan Ware.