Whittaker began competing in amateur freestyle wrestling tournaments in 2015, when he unexpectedly turned up to compete in the Australia Cup in Canberra. He won each of his three bouts.[64] It was also at the 2015 Australia Cup that Whittaker flagged the possibility of potentially representing Australia in Olympic or Commonwealth wrestling competitions.[65] He returned to the wrestling mat in May 2017 and claimed the Australian National Wrestling Championships gold medal in the 97 kg (213 lbs) division.[66] After winning the national championship, Whittaker entered Australia's 2018 Commonwealth Games 97 kg qualifying tournament in November 2017. He would once again claim first place in his division and in doing so qualified to represent Australia in the wrestling at the 2018 Commonwealth Games on the Gold Coast,[67][68] the city in which he made his UFC debut. Following his qualification, Whittaker made it clear he would only compete in the Commonwealth Games if the event did not interfere with his UFC commitments.[69] It was confirmed in March 2018 that Whittaker would be one of eight Australians to compete in the Commonwealth Games wrestling competition in April 2018.[70] However, Whittaker was forced to withdraw from the Games less than three weeks from the event in order not to risk being stripped of his UFC championship title, as the UFC was concerned that an injury incurred during the Commonwealth Games would render him unable to compete for the middleweight championship at UFC 225 against Yoel Romero on 9 June 2018.[71][72]
