Duinker went undrafted in the
2012 NBA draft. He later signed with
Cáceres CB of Spain for the 2012–13 season. In 35 games, he averaged 7.3 points and 5.1 rebounds per game. On 31 July 2013, Duinker signed with
Zorg en Zekerheid Leiden of the Netherlands for the 2013–14 season. On 17 June 2014, Duinker signed a two-year deal with the
Sydney Kings of the Australian
National Basketball League. On 15 December 2014, Duinker signed with the
Nelson Giants for the
2015 New Zealand NBL season. After being tested by
PBC Lukoil Academic in early September 2015, Duinker later signed with
Egis Körmend of the
Hungarian League for the 2015–16 season. In August 2016, Duinker signed with Argentine club
Regatas Corrientes for the 2016–17 season. In November 2016, he left Regatas and signed with Uruguayan club
Defensor Sporting for the rest of the season. He left Defensor in February 2017. On 8 March 2017, Duinker signed with the
Wellington Saints for the
2017 New Zealand NBL season, returning to the country for a second stint. On 11 April 2017, he was deemed a "restricted" (import) player for the rest of the 2017 season and beyond after Basketball New Zealand discovered Duinker made an appearance for the
Netherlands national team in 2013—he was originally classed as a naturalised local player due to having a New Zealand passport. For the 2017–18 season, Duinker joined Japanese team
Kumamoto Volters. ==Career statistics==