She is scheduled to undergo an MRI on her back on Monday in Indianapolis and will not be cleared to race before the results of the test are known, a spokesman for the series said.
Mann, whose only other IndyCar race this year was the Indianapolis 500, was set for her first race as part of the Rahal Letterman team before her car hit a wall during a morning practice run. She was helped out of the car and supported under her arms as she walked slowly to a stretcher.
She was awake and alert when she was taken to Concord Medical Center for evaluation.
Her car also spun on two practice runs Thursday and made contact with the tire wall in Turn 2 on the second run.
Mann finished 20th in the Indianapolis 500 for Conquest racing.
Rahal Letterman co-owner Bobby Rahal won the first IndyCar race at New Hampshire Motor Speedway in 1992.