Career
Ajax
Koppers began his footballing career in Utrecht, playing for the local amateur side SCH"44 in the town of Harmelen as a striker, before getting recruited by Ajax to join their youth ranks. Currently serving as a left back for the Ajax First Rate (at Lloyd's) youth selection, Koppers appeared in his first match for the senior squad on 23 October 2011, in the "Klassieker" derby against arch-rivals Feyenoord, starting in the left back position and playing the full ninety minutes in the 1–1 draw at home. On 31 January 2013 it was announced that Koppers would complete the 2012-2013 season with ADO Den Haag on a six-month loan spell.
While in The Hague, Koppers made 14 league appearances, helping his side to a 9th place finish in the league table.
Football Club Twente
On 23 July 2013 it was announced that Koppers had transferred to Football Club Twente on a four-year contract for a fee of €800,000. Willem II
On 22 June 2015, it was announced that Koppers would sign a deal with Willem World War II