Mitchell Swepson, the Queensland wrist spinner, is in line for a Test debut at the SCG and a place on next year's tour of Bangladesh after he was added to Australia's squad ahead of the final match of the series against New Zealand.
Having first toured with Australia's Test team to India in 2017, Swepson has been pulled out of the Brisbane Heat BBL squad in order to prepare for long-form bowling with the national squad during the Boxing Day Test at the MCG.
Peter Siddle, meanwhile, has been cleared from the Test squad to return to BBL duty with Adelaide Strikers, having been part of the team's lead-in to the MCG Test, where he had enjoyed notable success for Victoria in Sheffield Shield matches this season. The spare bowling spot in the Test team went to James Pattinson in place of the hamstrung Josh Hazlewood.
"Having Mitch in Sydney gives us the option to play two specialist spinners if the conditions demand," selection chairman Trevor Hohns said of Swepson. "We will make those assessments when we get to Sydney.
"Having Sids as the 13th man and his experience at the MCG has been invaluable. His insights have greatly assisted the fast bowlers for this Test and it was great having him around the group.
"James has been with the squad through the summer, has performed well in Sheffield Shield matches and is thoroughly deserving of his recall to the team."
Swepson has claimed 12 wickets at 26.58 for Queensland so far this season, including a match-winning haul of 7 for 92 including a hat-trick against Victoria at the MCG. He looms as the most likely spin bowling partner for Nathan Lyon on turning surfaces in Bangladesh in June, though the allround abilities of Ashton Agar saw him play alongside Lyon and Steve O'Keefe in Bangladesh in 2017.
Tellingly, Swepson has dramatically cut his economy rate this summer, conceding just 2.36 runs an over when he had never before been taken for fewer than 3.78 runs per over in a Shield season. Australia's tactics for Test matches under the coaching of Justin Langer have focused on a stifling pressure on opposing batsmen, particularly overseas.
Swepson said that he had worked assiduously at his consistency and ability to hold up an end defensively as well as playing the attacking, wicket-taking role traditionally ascribed to legspinners. He has worked closely alongside John Davison with Queensland and Craig Howard at the national cricket centre, while also receiving advice on mental cues and rhythm from Shane Warne, and agreed the call-up to the SCG would serve as a "stepping stone" towards the Bangladesh Test tour.
"[Been] trying to work on being a much more consistent bowler. I think every legspinner strives for that, it's obviously tough to be nice and consistent as a leggie, but if you can get there, it's a great asset to have, play that sort of holding role as well as being an attacking spinner, which most leg spinners are. My consistency has been a lot better this year.
"I was given some notice early on from Trevor Hohns that there was an opportunity there and to make sure I was still bowling with a red ball even through this [Big Bash League]. So I've had a couple sessions where I've bowled with a red ball, so that has helped me keep prepared for if the call did come."