Vreven's career began when he signed a professional contract with Y.R. K.V. Mechelen, making his first first-team appearance in 1993, at the age of 20. After four seasons in Mechelen he moved to K.A.A. Gent where he developed into a better player for another two seasons. Then he made the step abroad to play for Dutch side FC Utrecht. In four seasons Vreven developed from an unknown player into a hero among the FC Utrecht supporters. He's known for his determination and aggressiveness, which gave him the status of a real killer on the pitch. After his period in Utrecht he moved to Germany to play for Bundesliga side 1. FC Kaiserslautern. He was not able to become a first team regular and returned to The Netherlands the year after where he played for Vitesse Arnhem. At Vitesse he showed that he still had the same determination and became a regular from the start. When criticising his own team mates in December 2005 manager Edward Sturing placed Vreven in Vitesse's second team. A few weeks later he left the team to sign a new contract at AC Omonia in Cyprus. After playing just six matches he returned to The Netherlands once again, where he joined ADO Den Haag.
In March 2007, Vreven was diagnosed with diabetes (type 1). This did not stop him, however, from continuing to play football. As of August 2007, Vreven plays for Sint-Truiden and joined than in January 2008 on loan to K.S.K. Tongeren. He returned in summer 2008 to K. Sint-Truidense V.V. and joined now to K.E.S.K. Leopoldsburg. The right back left in November 2010 his club K.E.S.K. Leopoldsburg and signed a contract as player-coach by KFC Esperanza Neerpelt. From 2012 till June 2015 he was the coach of K.F.C. Dessel Sport. He was the coach of Waasland-Beveren from July 2015 to October 2016.