WEST Coast coach Adam Simpson labelled the Eagles "an average side" after their dismal defeat to Essendon on Sunday and forecast a number of changes ahead of the club's clash with premiership favourites Greater Western Sydney next round.

The Eagles were smashed by Essendon at Etihad Stadium, dropping to a 54-point deficit at half-time and finishing the game as 61-point losers.

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The Bombers completely controlled the contest from the start, with West Coast outplayed across the ground and well beaten in the midfield.

Simpson described the performance as "terrible" and put the heat on his leaders after the Bombers kicked 10 unanswered goals across the first and second quarters to set up their win.

WATCH: Adam Simpson's full post-match press conference

"We're 6-3 and bitterly disappointed in everyone. We've reflected on a few things we'll keep in-house and we've got some work to do. We're an average side and we're fighting for a spot in the eight. That's where we're at, you've got to be honest," he said post-game.

"Every team has gone through little moments like this; how we respond is what we need to look at.

"Good sides handle pressure and then they respond. Everything we tried today didn't work and we've got some work to do."

The loss came after three positive weeks for the Eagles, who followed their shocking round-five loss to Hawthorn with wins over Fremantle, Port Adelaide (at AAMI Stadium) and the Western Bulldogs.

The disparity in the Eagles' form concerns Simpson, with his side perhaps the most unreliable of the top-four contenders. They remain in fourth position on the ladder despite the loss and are a win ahead of the fifth-placed Power. 

Five talking points: Essendon v West Coast

"Going forward, how do we become consistent in effort and intent? It's something we need to get right because the gap between our best and worst is too inconsistent and it starts with our leaders," Simpson said.

"We've got to keep working through these situations and try to learn and educate and grow and develop the second tier and give them an opportunity to confront the group. We're in it together and hopefully we can back it up this week. We're looking for a response next week."

The Giants present a big challenge for the Eagles, who will leave Melbourne on Sunday anticipating a number of changes to the side ahead of next week's clash.

"I think we've got to look at it. We've got lots of players coming back, East Perth had a really good win on the weekend and there were probably five or six players who played pretty well in that game who we can look at.

"You've got to [make changes] when you have a performance like that."

Drew Petrie returned from a broken hand at WAFL level and played well on Saturday so will be in the mix to resume for the Eagles next week, while Will Schofield and Mark Hutchings could also be considered.