Fremantle have been dealt a major blow ahead of this weekend's Western Derby, with their skipper Nat Fyfe set to miss the clash.

Fyfe was knocked out following a sickening head collision with St Kilda's Josh Battle in last weekends win, and the former Brownlow medallist isn't underestimating the dangers of the injury.

"“I’ve had a lot of injuries over my career and concussion still sits at the top of the list, so I’ll be taking this extremely seriously,” Fyfe told 7NEWS.

“So the decision is this week, given the short turn-around and given how big the impact was, that I’ll sit out and reload to play next week.”

The 27-year old had started the year strongly prior to his concussion, with the midfielder amassing over 30 disposals in the first two games of the season.

The Dockers will be hoping to continue their impressive start to the season against the Eagles on Saturday night.