The trade Friday sends de Guzman to Dallas after logging 1,028 minutes for Toronto FC this season.
De Guzman is a four-year veteran in Major League Soccer. He has two goals and eight assists in 65 matches since joining Toronto FC from La Liga side Deportivo de La Coruna in 2009.
Wiedeman appeared in eight games for FC Dallas. A second-round draft pick in 2010, Wiedeman had five goals in nine preseason matches, but none in the regular season.