FREMANTLE duo Matthew Pavlich and Michael Walters have passed their concussion tests, but a decision on whether they play against Essendon will be in their hands, Dockers coach Ross Lyon says.

Pavlich and Walters copped heavy head knocks in the first half of the Dockers' win over Melbourne last Sunday at the MCG.

Neither man played after half-time.

Both players trained on Thursday morning, although Pavlich was on light duties.

Lyon said both had passed concussion tests earlier in the week but could not guarantee either would play on Saturday night at Domain Stadium.

"Not definitively," Lyon said.

"They've cleared all their tests but it's going to be up to the individual, how they feel, if they're symptom-free. This is our first real training session so we won't know. 

"They'll train. Matthew will partially train I would think. Michael is further advanced. I'm optimistic on both, but no guarantee on either."

Lyon said he would leave the decision in the hands of his players and the club's medical staff.

"I don't get involved," Lyon said.

"Our doctors make all the calls on all injuries. As long as they're symptom-free they're available to play.

"But then it really comes up to the individual as well.

"If there was any concern whatsoever it wouldn't even be a discussion, but clearly there are no concerns as we speak now.

"But that can change and shift quickly.

"We've got, at all times, our players best interests at heart, even though we're a hard-nosed professional football club."

The Dockers have held players over regularly in case of a late withdrawal, and Lyon said they would do so again on Saturday despite Fremantle's WAFL affiliate Peel Thunder playing on Saturday afternoon.

The Dockers have lost young key forward Michael Apeness for 10 weeks after he tore the posterior cruciate ligament in his knee last week, but they do have ruckmen Jon Griffin and Jack Hannath waiting and ready to play as key forwards if necessary, and dynamic small forwards Hayden Crozier and Max Duffy are also in good form.

Key defender Zac Dawson is edging closer to a return via the WAFL after suffering groin issues throughout the summer, but Lyon said the club would be cautious with Dawson given Alex Silvagni is out for three months with a hamstring injury.

"I think they're saying (Dawson's) ready to go if he gets through today," Lyon said.

"But in view of events, losing a couple, I'm more leaning towards giving him another week of full training, which would give him a month of full training.

"So he would come back in pretty good nick. That's exciting for us, that availability of a key defender.

"With losing Alex, it becomes paramount that he gets through unscathed for us."