SUNDAY'S Western Derby will pit a Fremantle midfield that is off its game against a West Coast group that has found its groove, making for a mouth-watering match-up that will be decisive in the crosstown clash.

When speaking after their respective round two matches, it was the midfield that Adam Simpson and Justin Longmuir both pointed to when explaining their contrasting performances.

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You suspect they'll be doing likewise on Sunday night, with West Coast reliant on its contest work in the middle of the ground to be competitive elsewhere and Fremantle's forwards desperate for better service from the midfield to get their season going.

"With contested possessions and clearances between the arcs, it's so honest the game at the moment. If you don't win the ball, you have to depend on back half ball movement," Simpson said after his team's 19-point win against Greater Western Sydney on Sunday.

The coach was talking about his own team's ability to win overall clearances (37-33) and control that area in the decisive second quarter (14-9), which saw the Eagles pile on eight goals against the Giants.

He could easily have been talking about Fremantle, and the back half ball movement the Dockers were forced to rely on after losing the overall clearances (30-45) in their one-point loss to North Melbourne on Saturday night.

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The centre clearance result (8-16) was even worse, with the Dockers conceding all three centre bounces in the second quarter and entering half-time with a 2-7 deficit.

The Dockers simply didn't have an answer for the strength and speed of Kangaroos star Luke Davies-Uniacke, who had 11 clearances for the match, including six out of the centre.

"Before we went on a little run in the last quarter, we were minus 10 centre bounce," Longmuir said after his team slumped to 0-2 on the season.

"Good luck trying to own field position with that number. We're better than that and we've got to start showing that."

The Dockers have grown to rely on a limited core of players to compete at centre bounces, with Andrew Brayshaw, Caleb Serong, Will Brodie and David Mundy taking the lion's share last season.

Swapping recruit Jaeger O'Meara for Mundy (retired) was the only change to that formula against St Kilda in round one, but Longmuir needed to move the magnets around against the Kangaroos and got James Aish and Sam Switkowski involved.

Longmuir said it's too early to say if he will try other options for Sunday's Derby, but second-year midfielder Matt Johnson, who has added strength to his 193cm frame, should be up for discussion to make his debut.

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Attacking wingman Nathan O'Driscoll, who worked hard on his inside game during the pre-season, should also be an option after recovering from a recent foot injury and lining up in a WAFL practice match for Peel Thunder on Saturday.

With Elliot Yeo (calf) still missing for West Coast, the Dockers won't confront the same type of size and power that Davies-Uniacke used to dominate Saturday night's contest.

But Tim Kelly produced a performance against GWS befitting an AFL star, while captain Luke Shuey and premiership hero Dom Sheed combined for 15 clearances, including seven out of the centre.

With No.1 big man Nic Naitanui still missing because of an Achilles injury, the Dockers should have a significant advantage in the ruck.

The scratchy form so far of new pairing Sean Darcy and Luke Jackson, however, means it won't be an overwhelming factor in the match unless the talented duo improves on the opening two rounds.

Listening to both Longmuir and Simpson after round two, it is clear what impact they believe their midfields can have on the rest of the team.

Simpson summed it up when he said: "Our biggest issue in the last two or three years is the contest. If we get that right and we're competitive in that area, then we can look at other things."

Right now, Fremantle finds itself in a position where both its forward line and conservative ball movement from the back half are under fire.

Get the midfield right on Sunday in a Derby that is up for grabs, and the rest can be addressed.