Bradley is tied for fourth in the Dutch Eredivisie's leading scorer list. He is Heerenveen's leading scorer, having overtaken Brazilian Afonso Alves, who has left for English club Middlesbrough.
Heerenveen is in third-place, nine points behind leader PSV and one point behind second place Ajax Amsterdam
Bradley left the Netherlands after Saturday's game to join the U.S. squad in Houston for its friendly against Mexico on Wednesday.
Miralem Sulejmani and Danijel Pranjic scored gave Heerenveen a 2-0 halftime lead. Bradley's 50th minute strike opened the floodgates. The goal was followed by goals from Roy Beerens (two), Gianni Zuilverloon and Thomas Prager.
It was the fourth straight win for Heerenveen.