The officer was found unconscious in his patrol car in Palmdale, a city near Los Angeles. The authorities appealed to the public for leads in the case.
The star pitcher was charged after a physical altercation on Sunday evening at a soccer stadium in South Los Angeles and later freed on $50,000 bail, the authorities said.
Bryant, the widow of the basketball star Kobe Bryant, sued Los Angeles County after some of its employees shared graphic photos of the crash that killed her husband and one of their daughters.