Paddy McCartin, who was recruited by St Kilda with the No.1 pick in the 2014 draft, suffered eight concussions before being delisted at the end of the 2019 season.

Tom McCartin, who was cleared of any damage to an artery in his neck after a pre-season scare in 2019, doesn't have the same history of head knocks.

But the Swans were rightly concerned when the 20-year-old's head slapped the Marvel Stadium turf after a marking contest on June 20.

McCartin is yet to resume training since that setback in Sydney's round-three match against North Melbourne, with coach John Longmire confirming he won't be ready to face Richmond on Sunday.

"Obviously with him, his family and Paddy; we understand what they've all been through," Longmire told reporters.

"We're conscious of that.

"We'd love to have him back in the team, but there's nothing more important than his own health and wellbeing.

"We're going to be mindful of that when he goes through his training phase, and just be really careful with it."

The Swans are unsure when McCartin will be ready for contact training and an AFL return.

"We're very mindful of just coming back slowly," Longmire said.

"He's fine walking around here, he's good, but (not ready) as far as exercise is concerned."

Australian Associated Press