The incident occurred shortly before 7:30 a.m. near Arlington Avenue as the officer was investigating a report of a pedestrian on the freeway, a CHP spokesperson said.
The severity of the officer's injuries were unknown. News video from AIR7 HD showed an ambulance transporting the officer to a hospital.
The Nos. 1 and 2 lanes of the westbound freeway were temporarily closed, and Nos. 1-4 lanes of the eastbound freeway were shut down in the area while an investigation was conducted.