The 21-year-old from Kawerau, who won the previous round of the BMX Supercross in South Africa last month, crashed during practice for the latest round in Chula Vista near San Diego.
She injured her wrist and is returning home to ensure a full recovery, cutting short on a planned trip to Europe including the final round of the Supercross in France.
"Sarah came up short on a big jump during practice and crashed," BikeNZ national BMX coach Ken Cools said.
"It was not a bad crash but she has re-injured her wrist. It has swollen quite badly and so we have decided that it's best for her to return home and ensure she gets a full recovery.
"It's a pity because Sarah is in such great shape but that's BMX.
"Crashes and injures are very much part of the sport and right now it's far more important for her to get healthy for the competition next year as we set about the Olympic qualification."
Her Beijing Olympic team-mate Marc Willers is also sidelined as he awaits a date for surgery on his injured shoulder.
Earlier Pukekohe 16 year old Trent Woodcock missed out on qualifying for the elimination rounds in the men's competition which was dominated by world champions Mike Day and Donny Robinson (both USA) and Maris Strombergs (Latvia).
