Justin Longmuir addresses Fremantle's players during their win over the Western Bulldogs in round 21, 2022. Picture: AFL Photos

FREMANTLE will keep a tight focus on Saturday night's Western Derby and resist any temptation to look ahead to finals, with coach Justin Longmuir wary that crosstown clashes don't always go to script.

The Dockers are heavily favoured to win Derby 55 against the 17th-placed West Coast in what could be champion midfielder David Mundy's last game at Optus Stadium if a home final isn't forthcoming in September.

Finishing top four will remain a possibility for the Dockers if they can secure a third straight Derby win, but Longmuir said September football had not been a talking point at Cockburn.

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"We talk about this being the most important game of the year. That's where our mindsets are, and that's what we need to go and execute tomorrow," Longmuir said on Friday.

"I don't know why everyone's talking about finals. We haven't spoken about finals and we don't talk about this week being a prelude to the finals.

"Come the end of the year, there can be a lot of distractions and players can shift their mindset to outcomes and finals down the track.

DO IT FOR DAVE: Longmuir appeals to players for big send-off

"We've got to make sure our players are really present and respect the opposition and go about improving our footy."

Fremantle's final match of the regular season is against GWS in Canberra in round 23.

Important forward Sam Switkowski will return from a back injury to play his first game since round 13, with the Dockers debating the merits of what will be a smaller forward line in the absence of Matt Taberner.

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"We feel Sam's in our best 22 and he's really important to the way we play, so that was where we landed in the end," the coach said.

"He came through the coaches' office last week and started campaigning, like they do when they get close to a return.

"That said to me he was ready to go last week mentally, and we got an extra week into him. We'll see how he goes tomorrow night."

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Longmuir said it was important for both the club and the team to send Mundy off in the right way in case the 372-game midfielder doesn't return to Optus Stadium.

Six days after West Coast champion Josh Kennedy's farewell, the coach had high expectations for his own veteran.

"We're hoping for eight," he joked after Kennedy's incredible bag of goals in his farewell game.

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"Like JK last week, we understand the significance of Dave's career at our club, and he deserves to be sent off in the right way.

"He probably just wants his career to finish and for him to walk out the back door ... but we also understand the significance, and you only get one opportunity to send your champions out."

West Coast coach Adam Simpson said he was looking forward to seeing what his players could produce in a "backs-to-the-wall situation" in front of a packed Fremantle crowd.

"There’s not many games these days that do have the Derby type of feel, so that will bring out the best in both sides for sure," Simpson said.

"But using it for motivation ... trying to pump up a Derby is difficult, because it lasts for 10 seconds as a player, and then you get on with a normal game.

"The atmosphere, the crowd, the pride, all those things are in the background, but you've got to stick to your process when you start playing."

Simpson, who hadn't noticed any 'hangover' since Kennedy's emotional farewell game last week, said the Eagles will continue to trial players in different positions in the final two rounds of the season.

With an eye to the future, he said No.1 ruckman Nic Naitanui was "more than likely" to finalise a contract for 2023 at the end of the season, with the club not worried about premiership forward Willie Rioli's out-of-contract status.

"He's been dealing with a fair bit the last five weeks, so we've respected Willie's situation," the coach said.