SAN DIEGO — A motorcyclist was seriously injured Friday afternoon after being struck by a small SUV near a freeway entrance in Shelltown, San Diego police said. It happened about 12:15 p.m. at Osborne Street and Marine View Avenue near exit and entrance ramps to north Interstate 5, Officer Tony Martinez said in a news release. The 32-year-old victim was riding his Kawasaki motorcycle north on Osborn when the driver of a Nissan Cube pulled in front of him, Martinez said. The motorcyclist tried to evade the SUV but could not avoid being struck. Martinez said the man suffered a broken left femur. Footage from OnScene TV indicated the rider was at least partially trapped under the SUV for a time, and Navy sailors who were nearby came to the man’s aid.