ST KILDA big man Rowan Marshall has been ruled out of facing Greater Western Sydney on Saturday as he deals with concussion.
Defender Jimmy Webster is also unlikely to play as he deals with a hip flexor injury, but is expected to be available the following week against Hawthorn.
In positive news for the Saints, Tim Membrey appears to have overcome a right knee injury and should be ready to return to the senior side.
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Membrey trained fully on Tuesday and needed to get through Thursday's main session, and subsequently pull up well, to face the Giants.
Marshall was the victim of friendly fire against Geelong last Sunday, sitting out the second half after copping a knock to the head from Jack Billings.
St Kilda will draw on its stirring 2017 win over frontrunners GWS to conjure an unlikely upset in their clash at Etihad Stadium.
The Saints have banked only one win this season while the Giants sit top after dropping just one of four games this season.
However, coach Alan Richardson said the Saints had proven they had what it takes to beat their opponents.
In round seven last season at Etihad Stadium, St Kilda claimed a 23-point win over the Giants after booting 10 of the last 13 goals.
The win was built on the dominance of their midfield with Seb Ross, Jack Stevens and Jack Billings starring.
So too did Koby Stevens, who will miss the GWS game with lingering concussion symptoms.
They will have their work cut out against in-form Giants onballers Callan Ward, Dylan Shiel and Stephen Coniglio.
"We know that they are an outstanding opposition but we had a really good result against them last year and I think that would give the team some belief, if we can get that footy back," Richardson said on Thursday.
"We know that we've been below our best and we've had a few too many down on form but if we can get close to 22 strong contributors than we will give ourselves a chance."
WATCH: Friendly fire floors Saint
Richardson said the Saints were planning for star midfielder Josh Kelly to play, despite the Giants saying he is likely to miss another week with a groin injury, as well as gun forward Jeremy Cameron (knee and foot).
"We've planned for their best team and that includes those two guys but the reality is that they have a strong list with a lot of depth and if those blokes don't play there will be a couple of quality replacements," Richardson said.
Meanwhile, the coach said defender Dylan Roberton was back at the club after collapsing behind play with a heart-related issue in the second quarter of last weekend's loss to Geelong.
"The testing will continue into next week and from all reports there's nothing at this stage that's obvious in terms of why he had the incident," Richardson said.
"He's good and while he has to be chauffeured around for the next six months he's in a really good head space and looks as good as gold."
