FREMANTLE'S season has hit another hurdle with giant ruckman Aaron Sandilands set to be sidelined for an extended period due to a collapsed lung, while skipper David Mundy is also set to miss a couple of more weeks with a calf strain.

The Dockers are 0-3 for the first time in Ross Lyon's tenure following their 33-point loss to West Coast in Saturday night's Western Derby.

Sandilands' injury rubs salt into a gaping wound. He copped a knee to his ribcage from Nic Naitanui in a marking contest in the second quarter and although he was able to get up, he walked slowly to the bench before being escorted by the club doctor down to the rooms.

The 33-year-old was then taken to hospital by an ambulance at half-time. He needed an oxygen mask to get to the ambulance but was walking without any assistance.

Full match coverage and stats

Lyon confirmed the ruckman had suffered some internal damage.

"Aaron's got a punctured lung and likely rib damage, so he went straight off to hospital," Lyon said.

"It's not ideal, but it's really courageous how he got up. It was a big contest. It was a result of a turnover. He got put out of position. It's really disappointing."

There is no time frame on the injury as yet.

Aaron Sandilands on the ground in pain after suffering a collapsed lung. Picture: Getty Images

Mundy did not play in the derby after he was withdrawn on Friday due to a calf strain he suffered at training on Thursday. Lyon confirmed the skipper would miss a couple of weeks with the injury.

Mundy also missed two games in the NAB Challenge due to groin tightness but did play in the first two rounds.

Sandilands' injury left Fremantle in dire straits in the ruck department, having not picked a back-up for the derby. Young key position player Alex Pearce shouldered most of the load against Naitanui and Scott Lycett.

How the fans saw it: Eagles v Dockers

Defender Michael Johnson and midfielders Michael Barlow and Matt de Boer were forced to ruck at times to give Pearce a rest.

"It wasn't ideal," Lyon said.

"We've gone without a second ruckman, banking Aaron could do a fair percentage. So that's probably debatable in the first place, because we've got Jon Griffin.

"(The Eagles) certainly got an ascendancy in the ruck out of that. We tried a few things, mobile ruckman, all those things. I thought Michael Johnson in the last quarter around the ground was actually OK for us. I'd be loathed to apportion that to the issues we're working through."

WATCH: Ross Lyon's full post-match media conference

Griffin is set come into the Dockers' line-up next week against North Melbourne after playing in the WAFL in the last two weeks. Zac Clarke is still nursing a knee injury he suffered in round one against the Western Bulldogs, while fellow tall Jack Hannath is also available if need be.