The crash occurred shortly before 9 p.m. near the Marina Market on Highway 20, according to the California Highway Patrol which, along with Northshore Fire, responded to the scene.
Reports from the scene indicated that the motorcycle was struck from behind by a vehicle.
The man, who was reportedly down on the ground and blocking one lane of traffic, had a fractured left femur and was advising paramedics that he couldn't move his legs, according to radio traffic.
It also was reported that the injured man was wearing a helmet at the time of the crash.
The man was flown to an area hospital, officials reported.
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