Former Adelaide ruckman Jon Griffin appears certain to make his Fremantle debut against the Saints at Patersons Stadium, with Sandilands this week ruled out for four weeks with "turf toe".
Fremantle has a 0-5 record without Sandilands since 2008, but Harvey said his side was better prepared to win games without the All Australian than it had been in the past.
"Individually Aaron's probably got better over the last couple of years, but I think the team's more equipped," Harvey said from Fremantle Oval on Wednesday.
"So at the moment I'm trying to work out what our best team is, because we're sustaining things with a lot of players being out.
"We're playing a side (St Kilda) that's been the most publicised team over the last two years, as in playing - they've played three grand finals - so we've sat back and watched them over the last two years.
"We got within striking range twice last year (and) we know we're getting a hell of a lot closer to beating those sides, so this is another hurdle for us."
Harvey said he was unlikely to use both Griffin and third-year tall Zac Clarke against the Saints, who have relied on Justin Koschitzke and Jason Blake in the ruck but might recall Ben McEvoy.
Griffin has averaged more than 36 hit-outs in seven WAFL games this season, and Harvey said the 25-year-old's 41 games of AFL experience counted in his favour at selection.
"Griffin we took to Adelaide with us and he was very close," the coach said.
"Kepler (Bradley) has probably exceeded expectations the way he's playing down there in the forward line particularly and we know that we lost Aaron late last year.
"It's very hard to find mature-age ruckmen like Jonathan."
Harvey said his midfielders would have to adjust their approach at stoppages without Sandilands' dominant presence, paying more attention to the opposition's ruckman.
Meanwhile, Fremantle has been boosted by midfielder Michael Barlow's progress as he recovers from a broken leg.
Harvey said the 23-year-old would join full training on Wednesday night and was on track to return via the WAFL in 10 days.
"He's going to need at least three or four or five weeks (in the WAFL)," the coach said.
"We'll be able to tell by the way he's playing as to how long that either takes for him to get back in the team, or whether we need to play him longer at WAFL level.
"I'd like to think he's playing Saturday week."
Fremantle is still managing the longest injury list in the AFL, with 12 players officially listed.
Key players Roger Hayden (foot), Alex Silvagni (groin), Nick Suban (leg) and Adam McPhee (knee) are sidelined, with only Hayden and Silvagni likely to return before the team's next bye in round 16.
Harvey challenged his 5-3 side to maintain its competitive performances until the break.
"That'll be the strength of the team moving forward, if we can sustain things under this regime at the moment," he said.
"Somewhere around the break that we have in five or six weeks' time, I'd like to think that we can get most of our guys back by that time.
"It'll be an interesting phase if we're within striking distance."
Nathan Schmook covers Fremantle news for afl.com.au. Follow him on Twitter: @AFL_NSchmook
