Oosthuizen attended Hoër Landbouskool Marlow in Cradock, from there he got selected to represent the Eastern Province Rugby Union at various youth tournaments, including Craven Week.
After school, Oosthuizen joined the Eastern Province Kings Academy and he was included in their Under-19 squad
In 2016, Oosthuizen was included in the Varsity Cup squad of NMMU Madibaz.
In March 2016, Oosthuizen was included in a South Africa Under-20 training squad and was named in the final squad for the 2016 World Rugby Under 20 Championship tournament.
In 2017 he was named in the NMMU Madibaz Varsity Cup squad once again. After the Varsity Cup he signed a deal with Griquas for the Currie cup and plays Top 14 rugby with the Southern Kings
Career
 |
Southern Kings Tighthead Prop |
2018 - present |
 |
Enisey-STM Loosehead Prop |
|
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South Africa U20's Loosehead Prop |
2016 - 2016 |
 |
NMMU Madibaz Loosehead Prop |
2017 - 2018 |
 |
Griquas Loosehead Prop |
2017 - 2024 |
