Sydney’s AFL premiership hopes have taken a big hit with uncertainty over whether star forward Lance Franklin will play any part in their finals campaign after being sidelined indefinitely due to a serious mental health issue.

The Swans released a statement and held a subsequent press conference to explain that Franklin had withdrawn from Saturday’s qualifying final against Fremantle because of that condition.

The club later sent out another statement, confirming that Franklin had also suffered a seizure last Friday while at a Bondi cafe and that he had a mild form of epilepsy.

He was subsequently hospitalised but the Swans said the two conditions weren’t related.

“This incident is not clinically linked to the mental health condition he is currently dealing with, and both Lance and the club have considered it a private medical matter,” the Swans said.

It is the second time this year Franklin has been hospitalised, the first coming in January when paramedics took the star forward to hospital from his Bondi apartment.

Swans coach John Longmire said on Tuesday that Franklin’s mental health condition was treatable, but refused to put a time frame on when he might return.

It was another setback for the Swans to deal with after losing Kieren Jack to a knee injury in their final round clash with Gold Coast and with gun midfielder Luke Parker already on the sidelines with a broken fibula.

“It’s a serious condition, that he needs to spend some time away from the football club, and he certainly won’t be playing this week,” Longmire said at the SCG.

“How long that will take, we’ll just have to wait and see.

“Obviously our thoughts are with Lance and we hope that he’s going to be okay.

“We understand he’s certainly got the best possible care to be able to address the condition that he’s got and we’re very confident that he will be able to get better very soon.”

Asked how long he had been aware of Franklin’s condition Longmire said “it’s been an ongoing issue for a while.”

Longmire stressed that Franklin’s condition was common and he was confident that he would not be looking at retiring, as was the case with former Melbourne forward Mitch Clark, who temporarily did so last year after he was diagnosed with clinical depression.

“We’ve got a lot of people who are able to deal with it and still be very successful and we’re very confident that’s the case with Lance,” Longmire said.

He wouldn’t confirm the exact nature of Franklin’s condition or whether he was in a mental health facility.

However, both Longmire and Swans’ co-captain Jarrad McVeigh referred to Franklin getting the best possible care and being in the best place for his condition.

“It’s a shock to a lot of the boys and `Bud’ is in a place now where he’s in the best area for him personally at the moment,” McVeigh said.

“We can just support him as a playing group and that’s what we’ll do as a footy club.

“Footy is the last thing on our minds in regards to his health and all the players have spoken about it and we’re fully behind him.”

Asked if the condition had affected the on-field performance of Franklin, who is Sydney’s leading goalkicker, Longmire said: “I think it affects your life.

“In regards to this you’ve got to put the football to one side a little bit in regards to Lance. You need to understand and respect that this is a challenge for him to deal with every day, it’s not just a football thing.”

Longmire said mental health was an issue he had addressed with the AFL commission.

Franklin 28, is in the second season of a nine-year, $10 million deal with the Swans after being signed from Hawthorn near the end of 2013.