Sydney Swans coach John Longmire has revealed Lance Franklin was never going to be considered for selection after his mental health battle was revealed last year, even if the Swans had made the grand final.

Franklin made a brave choice to announce that he was battling an ongoing mental health issue just days before the Swans' qualifying final against Fremantle, and ultimately didn't play another game for the season.

It meant the Swans travelled to Perth to take on the Dockers without their most influential player, plus injured midfield duo Kieren Jack (knee) and Luke Parker (ankle), and their best small defender Nick Smith (hamstring).

It's hard to imagine a bigger blow for Longmire on the eve of the finals, but in an exclusive interview with AFL.com.au, he revealed that even if the Swans had beaten Freo or North Melbourne the following week to keep their season alive, Franklin's name was never on the selection table.

"We made that call pretty early that (his recovery) wasn't going to be that type of development, it was always going to be a longer-term challenge for him," Longmire said.

"Coming back at that point, particularly if we were in a preliminary final or grand final, probably wouldn't have been the best thing for him.

"I guess it's hard for people outside to understand, but it's a big challenge and Lance's health was absolutely the number one priority.

"Whether you're a coach preparing for a final or not, that becomes the second priority and that's the way we dealt with that."

Franklin's star power hasn't dwindled at all since he moved to Sydney from Hawthorn in 2013 to escape the 'Melbourne footy bubble'; in fact he's become an even bigger drawcard in a city where AFL players are largely ignored by the media and general public.

With supermodel fiancé Jesinta Campbell also a very public figure, the 29-year-old still finds himself a star attraction in the social pages, but a practical Longmire said Franklin's profile has never affected his teammates.

"He's a big figure in sport and that's just the reality of it," he said.

"You just deal with it, and we're fortunate that we've got a really strong group of leaders, and inside the football club we focus on the football.

"Everyone outside the club looks at different things, and inside footy clubs it's all about concentrating on your training and talking about the way we play, and that's all the players focus on."

Since returning to the Swans for pre-season training in early December, Franklin has starred on the track. From the outside at least, his treatment for the unspecified mental health issues he's facing seems to be progressing well.

Aside from the odd greeting before training, Franklin is still yet to officially speak to the media, and while his progress looks to be positive, Longmire admitted the end of the road is still a fair way off.

"We know there's still some steps to be taken for him, it's not going to happen for him overnight," he said.

"It's still an ongoing challenge and he's still being supported that way, but as far as the football club goes and seeing him day to day, he's in great spirits.

"One of the things you have to deal with as a coach is to make sure you treat every individually differently, and you understand, and have great empathy for some of those challenges that pop up."

This season will be Franklin's third of the nine-year, $10 million deal he signed with the Swans and while the prospect of a key forward continuing into his mid-to-late 30s seems improbable, Longmire laughed when asked how may years his superstar had left.

"Hopefully seven," he said.

"That’s the plan, but you really don't know.

"We've just seen Adam Goodes play until he was 35, and he was weighing up whether or not to go on and play another year as a 36-year-old.

"What we do know is that if you prepare well and you're a great athlete and you get to the stage where you're really enjoying your footy like Lance is at the moment, who knows how long he can go for?"