FREMANTLE captain Matthew Pavlich has not ruled out spending more time in the midfield between now and the end of the season, despite entering Saturday's Derby in brilliant goalkicking form.

Pavlich, who is pushing towards a seventh All Australian jumper, has kicked 19 goals during Fremantle's four-game winning streak and has 47 for the season, just four behind Coleman Medal leader Lance Franklin.

The 2011 club champion said it had been nice to return to the forward line under coach Ross Lyon, but his role was "a moving beast" and there would be times when he needed to be injected into the midfield.

"Just because I've played forward for most of this year, it doesn't mean that I won't spend a bit more time in the midfield at times," Pavlich said on Tuesday.

"There was always going to be a combination (under Lyon) - it was just a matter of getting that split right, whether it was an 80-20 or a 90-10 [split]. The last few seasons it's been probably 60-40 mid-forward.

"Depending on where the state of the game is at and what needs to be done at that particular time, I think it's important to be able to chop and change a bit … that balance is really important."

Fremantle lost the clearances (30-39) and contested-possession count (136-140) in its 27-point win over Port Adelaide last Sunday, despite the impressive return of key midfielder Nat Fyfe.

Matt de Boer, who has moved into the engine room this season and is ranked No.2 at the club for contested ball, said the midfielders needed to "get to work a little bit" ahead of Saturday's clash with West Coast. 
 
"Our results from the last few weeks have been a little bit disappointing and we know that," de Boer said.

"We know that we've got a lot to work on to make sure our defence doesn't come under pressure and our forwards get the right opportunity.

"It's just a few structural things that we know we haven't executed like we should have."

Pavlich expected he would remain forward for Saturday's Derby, with a match-shaping duel against young key defender Eric Mackenzie looming.

The Eagles will be without captain Darren Glass, who has accepted a one-match ban for rough conduct, but Pavlich said Fremantle would still encounter a backline that "works as a group together".

He described Mackenzie as a strong key defender who had "really progressed with his work" this season.  

"I haven't played a whole heap on him but I've certainly watched a fair bit of footage in recent times," Pavlich said. 

"I'm impressed with what he does and it's going to be a big battle … he's able to stop the long leads and he's strong one-on-one."

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Lyon: Carlton Mid Derby one of the "nation's great rivalries"
From the Eagles: Glass accepts ban
Lyon lauds Pearce's hard work
Fyfe's a monster athlete: Lyon
Five Talking Points from round 18 v Port
We're ready for Eagles says Barlow
From the Eagles: Three Ds in doubt for Derby

Nathan Schmook covers Fremantle news for AFL.com.au. Follow him on Twitter: @AFL_Nathan