Lt. Richard Burke said the cause of the Monday afternoon fire remains under investigation. Damage is estimated at $250,000.
Hernandez and his wife, Sandra, were in Napa, Calif., at the time. His agent, Wil Polidor, says their two children were at a mall with their nanny and the pitcher's mother-in-law.
Burke said police have secured the home, which is uninhabitable.
King County public records show the 5,100-square-foot, five-bedroom, four-bath house was built in 2009 and is valued at $2.85 million.