Winnaar attended Dale College Boys' High School in King William's Town, earning provincial selections to represent the Border Bulldogs between 2013 and 2015.
In 2013, he represented the team at the Under-16 Grant Khomo Week held in Vanderbijlpark, scoring one try in the tournament in their 15–13 victory over Free State.
He was included in the squad for the NMMU Madibaz – a university rugby team that is affiliated with Eastern Province's Academy – for the 2016 Varsity Cup.
[6] Winnaar was amongst a large contingent of youngsters that were included in the Eastern Province Kings squad for the 2016 Currie Cup qualification series.
[7] He was named on the bench for their first match of the season against the SWD Eagles[8] and replaced Keanu Vers shortly after half-time to make his first class debut in a 14–37 defeat.