Sydney's Tom McCartin will spend further time on the sidelines in concussion protocols following another head knock over the weekend.

McCartin was ruled out of returning to the eventual five-point win over St Kilda in the fourth quarter following a collision with Saints debutant Max Heath.

The Swans defender was helped from the field and underwent assessment on the sidelines, with Sydney confirming McCartin was showing symptoms of concussion.

The club had made their sub change just moments later, with coach Dean Cox down to three bench options for the dying stages of the close encounter.

 Sunday, July 13 
Sydney WON BY 5 POINTS
Marvel Stadium
STK   
87
FT
92
   SYD

Speaking after the win, Cox confirmed McCartin, who has a history of concussion issues, had entered protocols but was looking good post-game.

"He's OK," the Swans coach said. 

"We entered (McCartin) into protocols. That's the first thing, just ruled him out of the game with symptoms and straight into protocols.

"He's OK now, we'll just assess symptoms in the next couple of days. We'll support him. He was walking around the changerooms, which was good.

"He is (concussed). Symptoms suggested that, and he'll go into protocols."

McCartin has spent numerous weeks out of action due to concussion in recent years, while his brother Paddy was forced to retire due to a series of traumatic head knocks.

The incident involving McCartin and Heath could be looked at by the AFL's Match Review Officer, with McCartin floored from a marking contest that saw his Saints opponent arrive second to the ball.

Cox said his priorities were elsewhere following the incident. 

"I didn't really have a look at the action. I haven't really seen it," Cox said. 

"I saw Tom, and my attention turned straight away to Tom. And then from there, what we're going to do. 

"We had already made a sub, so we had to get into play as quickly as we possibly could. Made sure Tom was right, then how we addressed the team. That was what I focused on." 

Sydney's latest win has them 12 points outside of the top eight with six games left in the home and away season, with the New South Wales side needing a near-perfect run home to play in September.

On a two-game win streak, Cox's side can extend that run to three with a victory over North Melbourne at the SCG this Saturday.