He attended and played rugby for Paarl Gymnasium and was selected for the Western Province squad for the 2015 Under-18 Craven Week tournament.
His team won the main match at the tournament held in Stellenbosch, beating Eastern Province 95–0 in the final.
After the Craven Week tournament, Grobbelaar was selected for the South Africa Schools squad that participated in the 2015 Under-18 International Series.
A 22–24 defeat to England in the semi-finals ended their hopes of winning the competition,[8] but they bounced back in the third-place play-off to beat France 37–15, with Grobbelaar scoring a further two tries.
[9] He made his domestic first class debut shortly after his return to South Africa, coming on as a replacement in the Blue Bulls' 54–22 victory over the Golden Lions in their 2017 Currie Cup Premier Division Round Three match.