Vreman spent his entire playing career with Dutch football club De Graafschap.

[1] His stay with the club earned him the nickname Mister De Graafschap.

On 3 January 2014, Vreman became interim manager of De Graafschap as a replacement for Pieter Huistra.

[2] On 25 March 2014, De Graafschap appointed Vreman as their permanent manager.

[3] In his first full season in charge, Vreman guided De Graafschap to promotion to the Eredivisie after beating Almere City, Go Ahead Eagles and FC Volendam in the promotion/relegation play-offs.