STAR Fremantle forwards Matthew Pavlich and Michael Walters are in doubt for the round six clash against Essendon after suffering concussion against Melbourne at the MCG on Sunday.

The pair took no part in the second half after copping the head knocks and the Dockers will have to wait before determining their availability for the game at Domain Stadium next Saturday night.

Walters failed to pass his concussion test after running into Demons opponent Lynden Dunn in the first term.

He sat out his 20-minute off-field period under concussion protocols, but was substituted out of the game in the second quarter for Matt de Boer.

Pavlich came off second best in a nasty head knock with Demons opponent Colin Garland after they careered into one another after a marking contest.

The Dockers skipper looked wobbly on his feet and was helped from the field by trainers just before the major break.

After Pavlich was assessed at half-time, the Dockers decided to take the cautious approach and kept him on the bench.

Fremantle coach Ross Lyon said once the doctor told him the players could not continue that was the end of the matter.

He described them as "head knocks" and said he was pleased with the way the team responded without the star duo.

"Walters put his head in the hole and copped a clip and Pavlich took a mark and took two steps and then copped a hit to the head, so it wasn't ideal," Lyon said.

Both players sat on the bench and watched the game and were walking around the rooms after the match.