West Coast coach Adam Simpson is confident his team can cover injuries to key midfielders in their season opener, when they host Brisbane Lions.

History suggests Simpson might be right, just last year injuries ripped through the West Coast defence. They not only withstood them but shone.

In 2015 key defenders Eric Mackenzie and Mitch Brown went down injured on the back of the retirements of captain Darren Glass and defender Beau Waters.

However, a more mobile and attacking defensive unit was a major weapon as West Coast made the grand final, before losing to the rampant Hawthorn.

The backline now looks ready for 2016 but it's West Coast's midfield that is struggling.

New recruit Lewis Jetta heads an injury list that includes Chris Masten, Dom Sheed and Sharrod Wellingham but Simpson is backing the depth the Eagles have built.

"We are used to that and hopefully we are developing some good flexibility in our squad so we can still win without our best team out there," Simpson said.

"To win games consistently you need probably 30 to 32 to pick from and we are always building on that.

"We are still evolving and always will be with the list changes. We made eight or nine changes to the list again this year but the depth of that squad is probably getting a bit stronger."

West Coast's biggest signing over summer was Jetta ahead of Jack Redden.

Jetta played 127 games for Sydney and won a flag in 2012 and while he won't be there Sunday, Simpson expects him there for a grand final rematch with Hawthorn in round two at the MCG.

"He was really close and we thought about naming him just to test him out but we just didn't want to play any games. We expect him to play next week," Simpson said.

"We need to get two or three sessions into him between now and then and I think he might be OK. I'm planning on him playing next week."