He seemed unfazed.
As his name was called among other dignitaries, de Blasio — dressed in a Mike Piazza jersey — tipped his cap to the booing crowd and continued his conversation.
The mayor, a Red Sox fan, was booed last year while standing with families of slain NYPD officers. He was also booed the year before, when he threw out the first pitch (a strike).
A spokesman for the mayor's office, Austin Finan, said “It wouldn't be a New York baseball game without a few boo birds in the stands.”