The 31-year-old Canadian international heads back to Germany, where he started his professional career after a stint at Olympique Marseille's youth system, after ending 2012 with FC Dallas of Major League Soccer. De Guzman was traded to the Texas outfit in July of last year by Toronto FC, with whom he had signed as the club's first ever Designated Player back in September 2009.
In four seasons with TFC, he made 93 appearances in all competitions, scoring three times. With FC Dallas, he featured 12 times with one goal.
Jahn Regensburg will be de Guzman's third European club since he made his pro debut in 2000, with the Toronto native having previously played for Bundesliga outfit Hannover 96 and Spanish side Deportivo La Coruna.