McCartin join Sydney's VFL squad this year after a long recovery from ongoing concussions sustained throughout his career, with the 25-year-old having suffered as many as eight serious head knocks in his tenure at Moorabbin.
After seeing medical specialists and taking a conservative approach to return to the AFL landscape, McCartin is nearing a second chance in the top flight.
The Swans emerged as keen suitors for the Geelong Falcons product earlier this month, with the spearhead likely to be recruited via next year's Pre-Season Supplemental Selection Period.
McCartin's potential addition to John Longmire's squad will bolster the Swans' key-position depths, with the likes of veteran forward Lance Franklin and McCartin's brother, Tom, doing most of the heavy lifting at either ends of the ground.
Speaking to 3AW this week, Longmire revealed McCartin remains in contention to join the Swans ahead of next season, with the club likely to trial the 35-gamer as a defensive and forward asset.
“He’s still in the mix (to be picked up by the Swans),” Longmire said.
“He’ll do some more training with us this year and we’ll look at him in the pre-season period, mainly to give him another opportunity to be able to show his wares.
“We were able to see him play a little bit of footy this year and we think he’s got the flexibility to play at both ends.
“But we’ll have to wait and see how that goes before that final decision is made.”
McCartin booted 34 goals across his five years with St Kilda, failing to make an appearance in the red, white and black in 2019 due to concussion before being delisted by the club at season's end.