The Olympic silver medallist, Sarah Walker, is in a race against time to be fit for the BMX world championships in Auckland next month.
Walker fractured her arm in a crash in the latest round of the US BMX Nationals in Illinois, where she is preparing for the world champs with the rest of the New Zealand team.
The team's coach, Ryan Hollows, says the injury is not too serious and Walker should be fit to race in a month's time.
Medical staff will assess scans to decide whether Walker will remain training in the US or return to New Zealand.