Career
His regular position is property Youth
Jonker was selected to represent Border in several youth tournaments. In 2007, he played for them in the Under-13 Craven Week competition, in 2010 he played at the Under-16 Grant Khomo Week and in 2012 he played at the Under-18 Craven Week competition.
He subsequently joined their academy and played for the Border U19 side in the 2012 and the 2013 Under-19 Provincial Championships.
Border Bulldogs
His first class debut came during the 2014 Vodacom Cup competition. With the Border Rugby Football Union in financial strife, they only had eleven contracted players on their books and gave opportunities to some of their academy players, with Jonker being one of those.
He made his debut in their Round One match against the Sharks XV in East London. He started all seven of their matches in the competition and also scored his first try in their final match against the Boland Cavaliers in Piketberg.