LEWIS Roberts-Thomson will reprise the role where he made his name, tagger Nick Smith will play and Sam Reid could help fill the forward/ruck role when the Sydney Swans face Adelaide on Saturday.

Heath Grundy's one-game suspension has been viewed as a significant blow for the Swans in their qualifying final at AAMI Stadium, as the 26-year-old has held down centre half-back in all 22 games this year.

Grundy's absence has been amplified by the need to quell fearsome Adelaide forwards Taylor Walker and Kurt Tippett.

But in Roberts-Thomson, who made his name with a starring role at full-back in the 2005 Grand Final victory over West Coast, the Swans have a ready-made replacement.

Swans coach John Longmire told sydneyswans.com.au on Wednesday he knows how fortunate he is to have a player like Roberts-Thomson with the experience to slot into such an important position.

"'LRT' has played a lot of footy down back," he said.

"It's very difficult to pluck someone out of the reserves who is six-foot-five and has a history of playing down back.

"You just can't do it … but we've got a bloke in our team that has played a fair bit in defence and played it well.

"That's the logical conclusion that you come to."

Roberts-Thomson has played predominantly as a forward in 2012, returning 22 goals from his 19 games, taking his career goals tally to 48.

He has also played an important role at times helping out in the ruck.

While he has only had sporadic appearances in defence this year, the Swans - who typically like to keep all bases covered - have still used 'LRT' in defence at times during training in case of just such an eventuality.

"He still trains there a bit," Longmire said.

"We still have him there at different times in some of our contested ball work that we do with our forwards versus defenders.

"So he's still been doing it a bit anyway, and we tend to make sure our talls are prepared for that and have done some of it during the year.

"Even though he's been playing forward and in the ruck, he's still done a fair bit of the contested ball work down back."

Reid - who missed last week's loss to Geelong with a minor glute problem - could now pick up Roberts-Thomson's slack as the forward/ruck option, judging by Tuesday's training session.

Shane Mumford and Mike Pyke share the rucking duties both in the centre square and at stoppages in the forward line, but Reid spent much of Tuesday's session doing ruck and contested marking drills with Mumford.

If a situation arises where Roberts-Thomson is in defence and one of Mumford or Pyke are on the bench, it is not inconceivable the 195cm Reid could spend time in the ruck.

Smith also trained freely after sitting out the Cats game with a tight hamstring.

"With Sam coming back, with another ruckman, you've got 'Goodesy' (Adam Goodes), we've got options in our forward line we can go to and use if need be," Longmire said.

"You saw [Reid] do his work yesterday and he was fine.

"I walked across to 'Gibbsy' (club doctor Nathan Gibbs) and said 'how was he and Nick Smith?' and they both seemed fine.

"At this stage we'd expect them to play."

James Dampney covers AFL news for sydneyswans.com.au. Follow him on Twitter: @AFL_JD