Fremantle’s senior coach, Ross Lyon, fears the absence of midfield duo, Michael Barlow and David Mundy, will have an adverse effect on Saturday night’s clash against Geelong.

At the beginning of the week Fremantle were hoping both key midfielders would be fit to make the journey to the Cattery.

Unfortunately for Lyon, Barlow hasn’t recovered from Monday’s jaw surgery and Mundy hasn’t bounced back from his recent calf injury that saw him sidelined at last week’s victory against North.

For Saturday night’s battle Lyon has called upon 19-year-old, Tom Sheridan, to join the list for the first time this year to play his second AFL game.

Despite Saturday night’s challenge, Lyon remains confident that his team has the ability to dismantle the Cats.

''It becomes incrementally harder [without Mundy and Barlow] but we've shown great capacity to lift up and everyone accepts challenges given to them,'' Lyon told Fairfax.

''That's made us a more versatile team. We know we've got a lot more through the midfield now.

Lyon is aware of where the Cats’ strengths lie and what is required to combat them.

''Geelong are a physical team. They hunt opposition players and they protect their own. So we welcome it, and it's going to be difficult.''