Siddle started to make a comeback to Test cricket in 2015, being brought into Australia's team for the 2015 Ashes series. He subsequently became a regular part of the Australian bowling lineup due to the retirement of Mitchell Johnson and an injury to Mitchell Starc. He played enough Test cricket to get himself back on a Cricket Australia contract, but in February 2016 he again had stress fractures in his back. As a result, he was sidelined for most of 2016, with a likely implication being that he had played his final Test match.