Boucher, who helped lead the Flyers to the 2000 Eastern Conference finals during an earlier three-season stint with Philadelphia, played in 18 regular-season games last season with the Chicago Blackhawks and Columbus Blue Jackets. He went 2-11-3 with a 3.34 goals-against-average last season.
With the Flyers, Boucher was 46-38-12, with a 2.45 GAA and seven shutouts, in 103 regular-season games from 1999-2002.
The 30-year-old goalie is 77-96-33 with a 2.79 GAA and 13 shutouts, in 220 NHL games over seven seasons with Philadelphia, Phoenix, Calgary, Chicago and Columbus.
The Flyers also signed 2006 first-round draft pick Claude Giroux on Monday to an entry-level contract.
A native of Hearst, Ontario, the 19-year-old Giroux had 48 goals and 64 assists in 63 games last season for the Gatineau Olympiques of the Quebec Major Junior Hockey League.