He was an instrumental part of South Africa winning the 2019 Rugby World Cup and received the Man of the Match award in the final.

He eventually followed his former coach Rassie Erasmus and joined the much larger and more competitive Western Province rugby union in 2009 after three seasons with the Free State.

While out with a neck injury, in June 2015 Vermeulen flew to France to be unveiled as a post-2015 Rugby World Cup signing for Top 14 club Toulon.

[6] After a short spell in Japan with Kubota Spears, Vermeulen travelled back to his home nation of South Africa as a Bulls-player, signing in October 2018.

One highlight of his appearances for the Emerging Boks was being in the squad that performed against the British & Irish Lions, holding them to a 13–13 draw, during their tour to South Africa in 2009.

After a stand out Currie Cup domestic Rugby Season, Vermeulen was named as part of the 39-man preliminary training squad ahead of the 2010 end of year grand slam tour to the Northern Hemisphere.

Vermeulen made his international debut for South Africa on 8 September 2012, where he formed part of the starting lineup going up against Australia.

Vermeulen received a man of the match award for his performance against England at Twickenham during this tour, based on a number of vital turnovers on the ground, 15 hard tackles, and his role of primary ball carrier on the day.