West Coast coach Andrew McQualter admits there is little chance of the Eagles being able to bolster their key defensive stocks through the mid-season rookie draft, saying they will almost certainly have to battle through the season with their current group of players.

The Eagles were overwhelmed by Fremantle’s tall forwards during Sunday’s western derby. The Dockers took 19 marks inside 50 and Jye Amiss dominated with 5.4.

Only Essendon have conceded more marks inside their defensive 50m arc this season than the Eagles, who continue to search for ways to replace premiership pair Tom Barrass and Jeremy McGovern.

Barrass moved to Hawthorn ahead of last season and then McGovern was forced to retire following multiple concussions.

Harry Edwards has played only one game this season after also being concussed and that has left West Coast with Reuben Ginbey, Sandy Brock and Tylar Young as their key defensive trio.

West Coast will have two selections in the mid season draft following long-term injuries to Deven Robertson and Jacob Newton, but McQualter said finding key defenders was a tough task.

“It is a position that every club in the land needs a bit of depth. There’s not a whole heap of depth across the country in the key back position,” McQualter told 7News.

“Our guys are working hard and if they find someone they think can fill that role and help our team, I am sure we will do that.

“We have lost a couple of midfielders for a long period of time, so potentially it’s some depth in that space.”

McQualter praised Ginbey for the way he has handled the pressure of playing on the opposition’s best key forwards. He kept Josh Treacy to only one goal on Sunday and that followed an impressive performance against Jeremy Cameron at Gather Round.

McQualter said Ginbey was doing an amazing job.

“He’s such a warrior. He had one of the toughest match-ups in the competition at the moment on Josh Treacy. He just finds a way to will himself and battle in a weight class that is often outside his own, he did a great job again,” he said.

While the backline was under permanent pressure, West Coast’s forwards struggled to kick goals. They booted only five majors for the day and their tally of 41 points was their second-lowest ever derby score.

But West Coast had plenty of early chances but kicked seven consecutive behinds before finally kicking a goal. Jake Waterman booted 1.4 after taking a series of shots from the boundary line.

McQualter said the Eagles had enough opportunities to make the game competitive. They had more inside 50s than Fremantle but paid a high price for failing to convert their chances and lost by 56 points.

“It was frustrating. If that scoreboard looks different, maybe the whole game looks a bit different,” he said.

“Our guys do a lot of work on their goal kicking. Sometimes you just have to own your moment out there. They’ll keep working hard on that.”