(DC)- Moments before the umpire says “play ball” tomorrow, Nationals Park will be quiet. A moment of silence will be held before the Nats’ home opener to honor five local police officers killed in the line of duty this year. Two officers injured in the line of duty will get the honor of throwing out the first pitch. Prince William County Police officers David McKeown and Jesse Hempen were shot while responding to a domestic violence call in February. Officer Ashley Guindon was killed in that shooting in Woodbridge.