WASHINGTON, DC - JULY 31: Vice President of the United States Joe Biden waves to the crowd during a military salute in between innings of the game between the Philadelphia Phillies and the Washington Nationals at Nationals Park on July 31, 2012 in Wa WASHINGTON - President-elect Joe Biden may already have one date on his calendar in the early months of his future administration:Opening Day at Nationals Park.The Washington Nationals announced Saturday night that the team is looking forward to having Biden throw out the first pitch on Opening Day next season:"We're excited to continue the long-standing tradition of sitting presidents throwing out the first pitch of the home of the national pastime in our nation's capital," The Nationals.