William "Billy" Edward Wagner (born July 25, 1971 in Tannersville, Virginia) is an American professional baseball player. A left-handed closer, he pitches for the Atlanta Braves of Major League Baseball. Previously, Wagner pitched for the Houston Astros (1995-2003) and the Philadelphia Phillies (2004-2005, the New York Mets (2005-2009), and the Boston Red Sox (2009).