FREMANTLE coach Ross Lyon has identified the clash of titan ruckmen Aaron Sandilands and Nic Naitanui as a key to the outcome of Sunday’s western derby, declaring it would go a long way to deciding whose terms the game was played on.

And Lyon acknowledged the fact that the Eagles have two genuine ruckmen, Naitanui and Scott Lycett, could influence his thinking when he trims his squad later today.

The Dockers coach has not ruled out using Alex Pearce as a back-up big man but also has 205cm Scott Jones in his squad.

“We rucked out of the back half last week with Alex Pearce and we thought he was quite mobile,” Lyon said.

“They are a really strong ruck combination. But there are a few teams that turn that on its head with a running ruckman.”

He labelled Sandilands and Naitanui as “clearly” the two best ruckmen in the competition.

“Everyone is looking forward to that battle on the weekend. I think it is going to be significant in the outcome. Both teams have faith in their prime ruckman,” he said.

“Lycett is also very competent so it is an extra load for Aaron and we have to consider that heavily.”

Lyon rated Sandilands’ dominant effort against the Bulldogs last week as “significant” in Fremantle’s comfortable win and said the influence a great ruckman could have on an outcome was still underrated.

“Around the stoppages, that pro-activeness. Both are wonderful ruckmen,” Lyon said.

“Once you are putting the ball and you know where it is going, (Nat) Fyfe and (David) Mundy and (Lachie) Neale can get on the move or (Luke) Shuey and (Elliot) Yeo and those types can get on the move to a clean hit... you get a little bit of momentum your way and a bit of surge going your way.

“It is significant and it gets undervalued by a lot of people I think.”

Lyon has indicated he is likely to stick with youngsters Andrew Brayshaw, Adam Cerra, Mitch Crowden, Bailey Banfield and Taylin Duman for the derby.

But he also said he felt he had improved his coaching by becoming a more “horses for courses” selector.

“We would like to reward performance. It has probably been a weakness of my coaching - that horses for course, team balance,” he said.

“I like to stick. Last week we made that call with Michael Johnson because of the height issue.

“Michael is a backman, they (West Coast) are a little bit taller, how do we go? We are still working through it.

“(Shane) Kersten and (Brennan) Cox have been in good form, and Shane Kersten was a bit unlucky to go out.

“We just wanted a bit more of a mobile forward line after round one and we put Mundy there, giving us another midfielder. He (Kersten) will come into contention with that.”