Lance Franklin has been ruled out of football for the rest of 2015.

Swans’ coach John Longmire says the star forward will continue indefinite leave from the club to seek treatment for an ongoing mental health issue.

"Lance won't be playing for the rest of the season. We're mindful of his mental health issue and it's something that needs to be addressed," Longmire said.

"That's his main priority, to get that right, so footy is not on the agenda for Lance for the rest of the season."

Forward Sam Reid has also been ruled out following a hamstring injury.

The Swans are looking to look to keep their season alive in Saturday's cut-throat semi-final against North after losing to Fremantle on the weekend.

In good news for the home side, Longmire said defender Nick Smith was a "big chance" to return, while young gun Isaac Heeney should be available to play after receiving a knock to his shin early in the game.