WASHINGTON - The Philadelphia Phillies tumbled out of a playoff position, getting swept in a doubleheader by the Washington Nationals when Yadiel Hernández hit a game-ending, two-run homer in eighth inning off Brandon Workman for a 2-1 win in Tuesday night’s second game.Philadelphia (27-29) lost its fourth game in a row and dropped behind Cincinnati (28-28), Milwaukee (27-27) and San Francisco (26-27) for the National League’s eighth and final playoff berth.“We’ve dug ourselves a hole and we’ve done that before and we’ve been able to fight out of it,” Phillies manager Joe Girardi said. “Now we have to win games and rely on other (teams).”The 32-year-old Hernández became the oldest player to hit a walkoff homer for his first big league home.