Sydney’s forward stocks have taken another hit, with key tall Tom McCartin ruled out for Thursday night’s AFL clash with the Western Bulldogs due to concussion.

The 20-year-old landed heavily in a marking contest during the final quarter of the Swans 11-point win over North Melbourne at Marvel Stadium on Saturday.

Already without injured spearheads Lance Franklin and Sam Reid, Sydney confirmed on Monday McCartin would not recover in time to face the Dogs at the SCG.

“The new concussion guidelines introduced by the AFL at the start of the year require players to return to a baseline level of symptoms five days out from a game,” Swans general manager of football Charlie Gardiner told the club website.

“With a short turn around leading into the Bulldogs on Thursday night, he won’t be cleared to play this week.

“We will be taking a very conservative approach with him.”

The Swans are still weeks away from welcoming back Reid (calf) and Franklin (hamstring).

Reid is poised to rejoin skills training later this week, while Franklin continues to up his workload.

But ruckman Sam Naismith is a chance to return from a hamstring complaint which has kept him sidelined for the first two rounds of the AFL restart.