FREMANTLE captain Nathan Fyfe is recovering well from his latest concussion and has returned to light running in the early stages of his mandatory 12-day period on the sidelines.

Fyfe is this week subject to the AFL's concussion protocols and ruled out of Sunday's clash against Carlton after a heavy hit against Greater Western Sydney in Sunday's 31-point win.

The dual Brownlow medallist completed a light running session on Thursday, both on his own and with a trainer for a short period, before leaving the track during ball movement drills.  

"The whole week he has looked really good. He'll take it really carefully," teammate Brennan Cox said.

Strong progress in his recovery this week could see Fyfe return against Hawthorn in round four if he passes all testing during his mandatory period on the sidelines.

The 29-year-old has spoken about how seriously he takes concussion, however, and how the injury can impact on a player's future.  

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Fyfe has now suffered three significant concussions since 2010 and visits an osteopath before every game.  

He took a strong stance and ruled himself out of the first Western Derby in 2019 after a sickening head clash with St Kilda's Josh Battle the week prior.

"At this point in time when I do the maths in my head, I'm still willing to put my body into those situations and I still see the risk as being worth it," Fyfe told broadcaster Mark Howard last year on The Howie Games podcast.

"I try and make that decision as a 45-year-old me or a 50-year-old me. But it's a very hard one."

Star forward Michael Walters is set to replace Fyfe in attack for Sunday's clash against Carlton and trained with the main group on Thursday after recovering from a hamstring injury.

Rookie forward Josh Treacy is also in the selection frame after serving his WAFL suspension.

Forward/ruck Rory Lobb is out of his knee brace and completed lateral movement work with a trainer away from the main group as he eyes a return in the next month.

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Cox said the Dockers were wary of Carlton after the Blues' 0-2 start to the season and they would be prepared for a fit and firing Patrick Cripps. 

"They get criticised and that's what fuels the fire and then they come out and throw it all at us," the defender said.

"But we'll be ready for it and can't wait for it.

"I expect them to come out firing, especially with 'Crippsy' as well.

"They'll come out and play their brand and I think they'll come out and really give it to us in the first quarter."