The production was shooting a scene in which actor Tom Sizemore was supposed to jump into a Cadillac SUV and remain seated until the scene ended.
Sizemore, however, reportedly put the vehicle into reverse and hit the gas, pinning the stuntman, reported Variety.
It's unclear what injuries the stuntman sustained, or where his condition stands, but he was airlifted to a nearby hospital after the car was lifted off of him with the help of equipment.
USA is yet to comment. It is currently unknown if the incident will affect production. Cal/OSHA is investigating, but did not offer further details on Wednesday.
Phillippe stars in "Shooter", which in February was picked up to series. Phillippe, who also produces, plays an expert marksman living in exile who jumps back into action after learning about a plot to kill the president.
Omar Epps and Sizemore also star in "Shooter", which is based on the Stephen Hunter novel "Point of Impact." The series is set to premiere on July 19.