Mastriet made his first team debut for the Blue Bulls in 2011. The player made several appearances in the Vodacom Cup competition over the next two seasons and made his Currie Cup debut in the 2012 Currie Cup Premier Division against the Free State Cheetahs.
Mastriet made his Super Rugby debut in 2013 with the Bulls and was selected to represent South Africa on the World Sevens circuit in the same year. The year 2015 saw him join the Golden Lions for which he currently plays.
(LS March 2016)
Career
 |
Eastern Province Kings Left Wing |
2016 - present |
 |
Bulls Left Wing |
2013 - 2014 |
 |
Blue Bulls Right Wing |
|
 |
South Africa 7's Fly Half |
2014 - 2015 |
 |
Lions Left Wing |
2015 - 2016 |
 |
Golden Lions Left Wing |
2015 - 2016 |
