Michael Walters and Matthew Pavlich are no certainty to face Essendon on Saturday as they race to overcome the effects of concussion.

Both were knocked out in Fremantle's 68-point win over Melbourne and Walters is tracking the better of the pair.

"He (Walters) was really good after the game so we are a bit more confident on him," Lyon told Crocmedia’s Sportsday program.

Walters subbed after hit to head

However Lyon was less sure about the chances of star forward Matthew Pavlich lining up on Sunday.

"Pav also copped a heavy hit against Sydney so it might be a compounding effect," he said.

"We’ll take no risk but really simply put there are tests they have to go through, if they pass the tests they play and if they don’t they’re not allowed.

Fremantle have won five straight games to start the season and many have suggested that the absence of Ryan Crowley, who is provisionally suspended pending an Anti-doping Tribunal hearing, has allowed the group to add more spark to the midfield.

Midfield mix crucial

"I thought they were writing us off because he (Crowley) was gone now they are saying we are better when he’s not there," Lyon said.

"You can’t measure it precisely. We played some pretty good footy with him in the side too.

"Clearly you have to be more proactive without him there but we tagged Travis Boak in round one, and haven’t tagged anybody since.

"There’ll be times when we need to go and lock someone down but at the minute it seems to be working."

When it came to the issue of Crowley’s anti-doping case Lyon put the accountability square on the player.

"Look I don’t go into it to be honest," he said.

"I control what I can control and there must have been good reason for them to do what they did but at the end of the day Ryan has got himself into this predicament and he needs to get himself out of it.

"It’s no good whinging about the process. You don’t want to get in it, but he’s in it and you’ve just got to work your way through it."

Lyon was also unconcerned by the fact Freo's victory on Sunday is one of only two trips they will make to the MCG this season.

"At the end of the day it doesn’t really matter does it? We’ll play anywhere. We hadn’t played much there before the finals in 2012 and did quite well," he said.

"You’d like to be there but don’t worry about what we can’t control so it’s not an issue."