[7] He recovered from an injury that kept him out of the 2014 IRB Junior World Championship to play a key part in the Sharks U19 side that played in the 2014 Under-19 Provincial Championship, making eleven appearances and scoring tries in their matches against Eastern Province U19[8] and Free State U19[9] to help them qualify for the semi-finals, where they lost 20–43 to the Blue Bulls U19.
[11] He made his Super Rugby debut in the Sharks' 27–10 victory, coming on for the final ten minutes of the match.
[12] In 2014, he was selected in the South Africa Under-20 squad to play at the 2014 IRB Junior World Championship, but an injury ruled him out of the competition and was replaced by Jacques Vermeulen.
[13] In March 2015, Du Preez was named in an extended South Africa Under-20 training group as part of their preparation for the 2015 World Rugby Under 20 Championship.
[16] He started both of their tour matches,[17][18] scoring a try in the 25–22 victory in the first encounter and was then included in the final squad for the 2015 World Rugby Under 20 Championship.