A 33-year-old man was gravely injured when he was hit by a pickup Saturday night near Mission Bay, San Diego police said. The pedestrian was hit by the eastbound Ford F-150 on Sea World Drive near Friars Road shortly after 9:30 p.m. Police said the man was struck after he walked into the path of the truck which was being driven by a 25-year-old man. The injured man was transported by paramedics to a hospital, where he was being treated for internal injuries considered life-threatening, police said. Alcohol was not considered a factor in the incident. No other information was immediately available.