Footage emerged on Monday of McCartin lashing out at Aaron Black during the match between Sydney and Geelong's reserves, with the ball nowhere near the pair.

Black avoided injury and was cleared of concussion, but the video shows him staggering backwards after McCartin appears to land a blow.

The incident was graded intentional, severe impact and high contact, meaning no early plea is possible and that McCartin will need to front the VFL tribunal.

McCartin joined the Swans' reserves for the 2021 VFL season, wanting to reignite a career that looked to be over after he suffered eight concussions while at St Kilda.

The key-position player is hoping to be picked up in the AFL mid-season rookie draft on June 2.

McCartin, who also suffered a thumb injury in the costly match, had otherwise made a very good impression on head coach John Longmire and other key figures at the SCG.

"It's very disappointing for Patty. He's a quality bloke, it's very unlike him and completely out of character," Longmire told reporters.

"I've had a brief chat with him. He's very remorseful.

"The main thing is Aaron is OK."

Longmire noted McCartin's thumb injury was sustained in a separate incident.

"He's only played a couple of games ... he was just getting back into it," Longmire said.

"This will set him back a bit, we'll wait and see how he goes after that."

Australian Associated Press