Saints first-gamer Max Heath is certain to come under match review scrutiny after he clumsily caught McCartin high early in the last quarter of the Swans' 14.8 (92) to 13.9 (87) win on Sunday at Marvel Stadium.
McCartin was floored by the impact and had blood on his face as he left the field, immediately going into concussion protocols.
The Swans backman has a history of concussions, and his brother Paddy was forced to retire from the AFL two years ago because of concussion issues.
"He's OK now, we'll just assess him in the next couple of days," coach Dean Cox said after the match.
"We'll support him, but he was walking around the change-rooms, which is really good."
Cox said he was unaware of the contact from Heath, who collected McCartin in a marking contest.
"I saw Tom and my attention turned straight away to Tom and from there, what we're going to do," he said.
An added complication was that Sydney had already activated their substitute, meaning they were down to three men on the bench for most of the frenetic last quarter.
"My ideal thing with the sub rule is if you have five players there, why can't they play? Do you need to have a sub? My thing is just play all five," Cox said.
Sydney are three games plus percentage outside the top eight, meaning everything has to go right over the last six rounds for them to sneak into the finals.
"We'll keep doing what we have to - even if we don't have one (a finals pulse), we want to make sure we finish this year off as well as we possibly can," Cox said.
Swans ruckman Brodie Grundy continued his impressive form and set up midfielder Errol Gulden for the match-winning goal with a hitout.
"That's the part about the tight contest, the ability for the good players to stand up when they have to," Cox said of Grundy and Gulden.
About the only thing Grundy did wrong all game was trying to take on Heath when he had a set shot at goal in the second term.
Grundy tried to run around Heath and was caught in a tackle, with the incident sparking a melee.
Cox praised his experienced players for their cool heads in the last term, when Sydney came back from 13 points down at three-quarter time.
"They certainly help ... just some really experienced players, and certainly behind the ball," he said.
"(They) really steady the ship."
Will Hayward kicked three goals and took a crucial defensive mark late in the final term, while Jake Lloyd also kicked three for the first time in his 265-game career.
Saints onballer Marcus Windhager, normally restricting opponents with his tagging, racked up a game-high 36 possessions.
Heath's mixed debut featured a goal.
Once again the Saints lacked nothing for effort, but were found wanting in their execution.
"The game was set up for us to win, we just couldn't quite capitalise," said Saints coach Ross Lyon
"They punished us, particularly early in the game when we were doing a lot right - some really simple turnovers.
"We're frustrated - and angry, really - but it's OK to be angry.
"It's what you do with your anger. It's OK to feel that emotion, but channel it into not dysfunction, not a pity party, channel it into improvement."
6°C