FREMANTLE'S challenging trip to face League leaders Adelaide has become even tougher with giant ruckman Aaron Sandilands ruled out of Saturday night's clash.

Dockers coach Ross Lyon has revealed that Sandilands, who leads the AFL for hit-outs (45.7 per game), is battling hamstring tightness and wouldn't be fit to take on in-form Crows star Sam Jacobs.

"(His hamstring is) just a bit weaker than we would like it. The scan was clear … we need to get it strong again," Lyon said.

"Hopefully (it's only one week), that's what we're aiming for.

"We'll bring in Jon Griffin (and ask him) to execute your role. Everyone brings something different to the table.

"Jon plays with a real passion and he's carried the number one ruck spot years ago for us when Aaron's been out and done really well, so we don't expect any different."

The Dockers will make at least two changes with half-forward Ed Langdon succumbing to a knee injury after playing sore in last Sunday's win over Carlton.

Hayden Ballantyne could have been in the mix to replace Langdon, but the goalsneak has been sidelined by another hamstring setback suffered in his comeback game for Peel.

Lyon insisted the 29-year-old wasn't rushed back too early from tendon surgery in March.

The midfield battle looms as the pivotal contest at Adelaide Oval, with Lyon declaring that pressure would be the key to limiting supply to the Crows' damaging forward line.

Adelaide boasts the most potent attack in the competition, led by superstar small forward Eddie Betts.

Betts has made a habit of kicking freakish goals in Sir Doug Nicholls Indigenous Round, and sits third in the Coleman Medal race with 28 majors.

"We all acknowledge that from leaving Carlton probably with issues and not as focused as he's always been, he's become an absolute pro and a leader of their football club," Lyon said.

"He's a real measuring stick, isn't he? When he's up and about he inspires his team.

"It's important as a team we give him the respect he deserves."

Dockers defender Lee Spurr could be tasked with standing Betts, while Connor Blakely might be sent to gun onballer Rory Sloane.

Sloane bounced back to form last round with 31 touches in a rout of the Lions, after being shut down by taggers in Adelaide's losses to North Melbourne and Melbourne.

"We've tagged him before. I think Tommy Sheridan last year went to Sloane, so we respect him highly," Lyon said.

"On the weekend, it was a loose eye on (Carlton skipper Marc) Murphy but Connor went and got 33 of his own, so we're not just locking down.

"It might be try and control him and work off at the right time."

Freo could field eight indigenous players against the Crows.

Griffin is likely to join Michael Walters, Brady Grey, Joel Hamling, Danyle Pearce, Michael Johnson, Stephen Hill and Bradley Hill in the Dockers side.