Having headed into the premiership decider favoured to beat the Western Bulldogs, the Swans led by two points at half-time but conceded six goals to three after the long break, ultimately falling to the Dogs by 22 points.

It was the Swans' second grand final loss in three years, and a bitter blow for the club - who defied the odds in 2016 to claim the minor premiership and storm back into flag contention after bowing out in the second week of the finals in 2015.

Up against the irrepressible force of Luke Beveridge's Dogs, the Swans had little luck on the day. Superstar forward Lance Franklin hurt his ankle early in the first quarter, and while he played out the game the former Hawthorn champion was subdued - finishing with 16 disposals and just one goal.

Then early in the last term gun midfielder Dan Hannebery was the victim of a sliding tackle from Bulldog captain Easton Wood, suffering an injury that Longmire said was a medial strain. Hannebery was assisted off the ground by club trainers, and while he briefly returned to the field, his game would end prematurely. Then there was the free kick count, which Sydney lost 20-8.

But rather than blame his side's lack of fortune on the day, Longmire paid tribute to the Bulldogs, and said his men didn't commit themselves sufficiently.

"We came up against a very, very good team," Longmire said on Saturday night.

"From our perspective we probably needed to work a little bit harder, a little bit more consistently over the four quarters. I think we weren't quite up to the workrate we normally get from our group. Probably the Bulldogs' consistency over their 22 versus ours. We didn't have as many contributors on the day that you need to have if you're going to be victorious. In the end you need everyone with their shoulder to the grindstone. We didn't have that even contribution that we definitely needed."

Asked about Franklin's opening quarter setback, Longmire was again reluctant to bemoan his team's fate.

"Those sort of things happen," he said.

"He was OK. Once that happens in the first couple of minutes you've got to get on with it. You've just got to do it."

The lopsided free kick tally was inevitably going to be a talking point, but Longmire kept his composure when the matter was raised.

"In the end all you can ask for is that they get paid both ways, and I'd have to sit and have a look in the cool light of day before I can comment on that," he said, having initially smirked in response to the question.

Swans chief executive Andrew Ireland said after his club's preliminary final win over Geelong last weekend that the club did not need a premiership to justify the hefty nine-year contract handed to Franklin at the end of 2013, but the pressure will only intensify after the Swans blew another chance on football's biggest stage.

While they were much more competitive on Saturday than in their defeat to the Hawks two years ago, Longmire said the pain would be just the same.

"They all hurt. There's none worse than the other. They all hurt," Longmire said.

"We sit here today with extreme disappointment and not only internally but also for our supporters. We're extremely disappointed with that. That's taking nothing away from the Doggies, they were outstanding."

Sydney will still enter 2017 as one of the favourites for the flag, but questions remain about the composition of their list next year.

Midfielder Tom Mitchell was among the Swans' best on Saturday with 26 disposals and two goals, but appears to have played his final game for the club.

Out-of-contract, Mitchell has been strongly linked with a move to Hawthorn. Longmire said he was uncertain about whether Mitchell would be at the club in 2017.

"I don't know. We've got to get through tonight before we worry about that," Longmire said.

The future of veteran small forward Ben McGlynn is also unclear. McGlynn experienced grand final heartbreak on Saturday, having missed out on premierships with Hawthorn (2008) and the Swans (2012), as well as playing in the Swans' losing grand final effort two years ago.

Questioned about whether McGlynn would continue in the AFL next year, Longmire said: "I'm not quite sure yet. We'll work that out as the weeks progress."

One man who will be with the club next year is Josh Kennedy, who starred with 34 disposals and three goals to run second behind Bulldog Jason Johannisen in Norm Smith medal voting.

Longmire was full of praise for the tenacious midfielder.

"Josh I thought had a real go for the whole game as he always does," he said. "He stands up in big games He plays well in big games, he thrives in the contest and did again today."

Kennedy said the defeat was more painful than the 2014 loss.

"The feeling's probably worse ... I think it probably hurt a little bit more because we felt we had a chance," Kennedy said.