A "shattered" Dane Rampe had a cry with Callum Mills after the Sydney captain was ruled out of the AFL grand final due to injury.

The veteran defender will lead the Swans in Mills's absence when they face the Brisbane Lions in Saturday's decider at the MCG.

Mills hurt his hamstring at training after playing in Sydney's qualifying final win against GWS and missed the preliminary-final victory over Port Adelaide.

Despite training well on Wednesday, Mills was ruled out of returning for the grand final.

Rampe described being captain as Sydney attempt to win their first premiership since 2012 as "bittersweet".

"First of all, shattered for a mate," Rampe said on Friday.

"One of my great mates and leaders of our club; we've been a lot through a lot together.

"Me and him had a cry after the news on Wednesday afternoon, but as soon as that was done, and the way Millsy would have wanted, it was business as usual."

It has been a difficult first season as sole captain for Mills.

The midfielder-defender didn't play until round 18 after badly injuring his shoulder during a Mad Monday wrestle gone wrong.

When Mills returned to the team, the Swans went through a concerning slump after sitting on top of the ladder since round eight.

Swans coach John Longmire and his football department were conscious not to make the same ill-fated decision they did for the club's disastrous 2022 grand final appearance.

Now-retired tall Sam Reid's bid to play off an adductor injury was a talking point in the lead-up to the decider, but the Swans opted to risk him.

Clearly struggling with injury, Reid was subbed out of the game after having no impact as Sydney suffered a humiliating loss against Geelong.

"It's one of those things you've got to make decisions, you sit down as a group, a medical conditioning staff and you go through everything," Longmire said.

"It's tough because Callum's a great person and a great leader of our footy club, but he also understands that decisions need to be made.

"When we sort of weighed it all up, and the risks going into a game like this, it just seemed to outweigh and go against Callum in that moment."

Mills will instead sit on the Sydney bench during the match as the Swans attempt to atone for grand final defeats in 2014, 2016 and 2022.

"His leadership and everything he does off the field hasn't wavered," Sydney midfielder James Rowbottom said.

"He's had a pretty rough year but his demeanour and the way he carries himself amongst the group and how he's still able to lead us is second to none."

AAP