Sydney coach John Longmire believes his side must stop two of the AFL's best forwards - Nick Riewoldt and Stephen Milne - to beat St Kilda and advance to the next round of the finals.

Longmire said the Saints have no shortage of match-winners across the field but it was Milne and Riewoldt who he lavished with the most praise on Tuesday ahead of Saturday night's elimination final at Etihad Stadium.

"They're two of the best forwards in the competition," Longmire said.

"Milne has kicked over 50 goals for the year as a small forward, he's one of the best small forwards I've seen for a long period of time.

"We know Nick Riewoldt at his best is a great player as well."

Nick Smith held Milne to just one goal when the Swans downed St Kilda by 15 points in round 22, while Riewoldt - hampered by a persistent left-knee injury and a blow to his head - booted 2.1 from 15 possessions.

Ted Richards, who blanketed Riewoldt in that game, admitted it was a different prospect this weekend.

"That was three weeks ago and I think quality players normally play well in finals and they really step up, so that is something that I'm going to be conscious of this week," Richards said.

Not only is Riewoldt likely to be primed for a big game but the Saints' side is likely to be significantly different.

Full-forward Justin Koschitzke and fullback Zac Dawson were late withdrawals in Sydney due to gastro, while Michael Gardiner has since returned to the team.

"Riewoldt will be less of a focal point and he will be supported by Koschitzke down there," he said.

"I think also Zac Dawson didn't play last time and against Carlton he went forward a bit too.

"It will be a different game."

Longmire said it would require a team effort to stop the Saints' potent forwards.

"We've been really pleased with our defence all year. We think our back six have done very well, but it is about our all-ground defence," he said.

"It's not just on our defenders but it's a responsibility on our midfielders and our forwards to make sure that the ball that does go into St Kilda's forward line is not on a plate."

Longmire was hopeful key defender Heath Grundy, one of two late withdrawals in the Swans' last-start 52-point win over Brisbane, would be fit to take on the Saints.

Grundy pulled out of the last game of the regular season due to a virus and has missed a handful of games this season due to illness but Longmire said it wasn't an ongoing issue.

Grundy didn't take part in Sydney's light training session on Tuesday but Richards suggested his team-mate would be right to take on the Saints.

The side's other late scratching from the weekend, Sam Reid (calf tightness), looked sprightly at training and will fly to Melbourne as planned on Wednesday for his AFL Rising Star nomination.

Veteran midfielder Ryan O'Keefe, who left the field clutching his left shoulder late in the victory over the Lions, has been passed fit while old hand Lewis Roberts-Thomson returned from a calf injury on the weekend in the seconds.

Brought to you by AAP © 2024 AAP