Andrew McGlashan is a deputy editor at ESPNcricinfo
Nepal Tri-Nation (1)
WCL 2 (1)
Ranji Trophy (2)
PSL 2024 (2)
BAN v SL (1)
With the Ashes secured and England providing weak opposition there is a school of thought that the upcoming Test is a prime opportunity to blood Swepson, the Queensland legspinner, ahead of Australia's overseas campaigns in Pakistan and Sri Lanka later in the year.
The emergence of Cameron Green as a viable option for a third quick, having had a major impact with the ball this series, would allow Australia to field a balanced attack. But showers are forecast throughout the contest while the SCG has not been a happy hunting ground for spinners of late.
Lyon bagged a 10-wicket match haul against New Zealand in 2019-2020 but averages 40.94 on the ground while over the last decade spinners have averaged 48.17 - the third highest of all Australia's men's Test venues.
However, Swepson is as ready as he'll ever be for his chance at Test cricket. With all three of Australia's World Test Championship away series in the current cycle on the subcontinent, he could have a big say in how the side builds on their Ashes success.
"I think Swepo has been Queensland's best player for a number of years," Lyon said. "Obviously I'm a big fan of spin bowlers so probably watch him a lot closer than what I watch Marnus [Labuschagne] or Uzzie [Khawaja]. He's been around our group for a long period of time now and when he gets his opportunity, no doubt he will take it and run.
"I'm excited about our relationship, our friendship is fantastic already, but really excited about the opportunity to bowl in tandem with Swepo whenever that may come, whether that's here in a couple of days or in Hobart or in Pakistan."
"I love bowling in partnership with spinners for sure. I've done it a lot in subcontinent conditions so if the opportunity does come to play two spinners I know we'll really enjoy building that partnership. We've been doing it in the nets but it's a lot different."
Usman Khawaja is likely to replace Travis Head in Sydney•Getty Images
Lyon did not believe a dodgy forecast (not entirely unusual for a Sydney Test) had to spell the end of Swepson's hopes although it strengthens the likelihood that Australia will retain their usual balance. Josh Hazlewood is expected to train fully on Monday as he continues his recovery from the side strain he picked up in Brisbane and it could yet be that Scott Boland does not retain his place despite the 6 for 7 he claimed in Melbourne.
"It seems to be every time we put stumps in the ground here it brings the rain which is unfortunate," Lyon said. "Does it become a bit challenging for spinners? Yeah, it can if the ball gets wet, but we are pretty lucky these days with the quality of the groundskeepers who make the surface pretty dry and the ground drains pretty quickly."
Swepson will only be selected if he is genuinely part of Australia's best attack to win the match with World Test Championship points available and the hunger to take the series with a whitewash to extend England's barren streak in Australia that dates back to 2010-11.
"There's no more dead rubbers - and I've never considered them when you wear a baggy green - firstly because there's the World Test Championship and we want to go 5-0 up," Lyon said. "If the conditions suit then we pick the best team to win that Test to make sure we keep moving forward. The Ashes for me is the pinnacle but I'd love to be part of a Test Championship final to state our case for the No. 1 team in the world."
Australia's squad will be bolstered on Monday by Mitchell Marsh and Josh Inglis who were driving up from Melbourne on Sunday - to avoid the risk of a commercial flight - having been added to as cover following Travis Head's positive Covid-19 result which has ruled him out. Usman Khawaja is expected to come into the XI.
Marcus Harris is also driving himself to Sydney having not joined the team's charter flight as an extra precaution after he dined with Head. Nic Maddinson will remain in Melbourne for now but continues to be a stand-by player. All Australian squad members, staff and families returned negative results in the latest round of testing.
This will again be the traditional Pink Test at the SCG which has become a central part of the Australian cricket calendar to raise funds for the Jane McGrath foundation. But Glenn McGrath will be unable to take part in the lead-up activities and at least the first two days having tested positive for Covid-19. It is hoped he may be able to attend by day three on January 7 which is the official Jane McGrath Day.