Newsom and Philadelphia Mayor Michael Nutter have agreed that the losing team's mayor will don the winning team's cap at an event on or around Veterans Day.
Newsom won his bet with Atlanta Mayor Kasim Reed after the Giants beat the Braves in the first round. Reed had to hoist the Giants' flag over Atlanta City Hall.
But the mayor's odds of winning this time appear slimmer. The Giants are considered significant underdogs against the Phillies, who finished with the best record in the majors this year.