WEST Coast coach Adam Simpson is keeping his plans to nullify Melbourne giant Max Gawn a closely-guarded secret, but says the Eagles won't deviate much from the formula which has them on the brink of a shock Grand Final appearance.

Gawn dominated when the teams met in round 22, picking up 10 AFL Coaches' Association votes for his 20-disposal, 41-hit-out display as the Demons rolled West Coast by 17 points at Optus Stadium.

The third favourite for the Brownlow Medal, Gawn ignites the Demons' hard-edged midfield brigade, and looms as the major stumbling block for the Eagles in Saturday's preliminary final without Nic Naitanui.

West Coast will be relying heavily on Scott Lycett and Nathan Vardy to make life difficult for Gawn, but Simpson insisted there had been no bigger focus on the dominant 208cm big man than usual.

"There's been no extra planning, it's just how we prepare normally," Simpson said.

"Our focus has been a lot about us and just playing the way we play and trying to help out when we need to with some of the quality that Melbourne have got.

"All those conversations (about restricting Gawn's influence), they're had, without telling you exactly what we're going to do.

"But I think the most important thing is we play our way."

Gawn's importance to the Demons was highlighted by intense media attention when he sat out a light training run on Monday.

But he was among an advance party of Melbourne players who arrived in Perth on Thursday and will be ready to go in a full-strength engine room, bolstered by the return of bull Jack Viney since the club's last trip west.

Viney has drawn comparisons with Geelong skipper Joel Selwood for his inspirational feats in the heat of battle, and adds another ball-hunter to the best contested-possession team in the competition.

Breaking even, or at least not being smashed at the coalface, is a major focus for the Eagles, who are 0-6 this year when they have been beaten by 12 or more in contested ball.

"The midfield battle is really important. The contest is really important. Everything's important," Simpson said.

"For us to go too hard at one particular thing is really dangerous, so we're just trying to play our way and be aware of their strengths as well."

The Eagles have made one forced change from their win over Collingwood, with veteran defender Will Schofield earning a recall to replace Brad Sheppard (hamstring) after being gut-wrenchingly left out of the qualifying final.

"I told him earlier in the week, he didn't jump out of his skin. He was like, 'Yep, no worries, I'll get on with it'," Simpson said.

"He's an experienced campaigner. It was a different conversation than against Collingwood. Telling someone they're in is pretty easy."

Melbourne dropped forward Bailey Fritsch, who has played every game bar one this season, to bring in defensive support, recalling Joel Smith to help combat West Coast's tall forwards in the air.

Changing a winning team came as a surprise, but Simpson didn't take heart from seeing the Dees plot ways to harness star forwards Josh Kennedy and Jack Darling.

"It doesn't make me feel any different. That's up to Simon (Goodwin) and his match committee," Simpson said.

"All we do is look at the final 22, see how we're going to play against them and get our match-ups and the way we want to play right.

"Selection has got nothing to do with me."

The Eagles boast a perfect 11-0 record with both big men in the line-up this year, and effectively had neither last time the teams met with Darling suffering concussion 10 minutes into the game while Kennedy was sidelined through injury. 

"We were really happy with some of the things we did last time without those two," Simpson said.

"We had to change slightly the way we moved the football, so it became a very ballistic game.

"These guys just give you something different in the front half, they give you a target to kick to and they're pretty hard to stop when they're at their best.

"They're important for us, but getting supply is I think the main issue for both teams.

"Melbourne are the best in the comp at the contest, and they're a really high-scoring side.

"We're aware of those two things in particular, but we've got strengths too."