GREATER Western Sydney has been dealt a massive blow ahead of Saturday's clash against North Melbourne, with co-captain Phil Davis to miss the trip to Tasmania due to concussion.

Davis was knocked out during the third quarter of the Giants' loss to West Coast last week, when he was collected by Jack Darling's elbow in a marking contest.

The 27-year-old was restricted to walking laps while his teammates completed their main session on Wednesday morning.

Davis will be replaced by fellow key defender Tim Mohr, who will play just his 47th game in his seventh season, and his first since round 10 last year.

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GWS coach Leon Cameron said Davis should be right to face Essendon at Spotless Stadium in round 10.

"He's feeling better, but it was a really big hit as everyone would have seen," he said.

"He had some headaches on Sunday and Monday, (and they were) minor yesterday.

"But with the concussion protocol, obviously if you get to Wednesday and you still have some symptoms that rules you out.

"It's disappointing we're not going to have him this weekend."

Davis joins the Giants' extensive injury list, which already includes stars Josh Kelly (groin), Toby Greene (foot), Brett Deledio (hamstring), Tom Scully (ankle) and Zac Williams (Achilles).

Forward Matt de Boer (hamstring) will also miss the Kangaroos game after being forced off in the first half against the Eagles.

Watch: Jack Darling's elbow collects Phil Davis

Cameron said Kelly – who has already been absent for the past five games - was a chance to return in round 10, with the club choosing to give the All Australian midfielder another week off.

The Giants initially thought that Deledio's hamstring issue was a minor one, but Cameron said the veteran did some damage to his tendon against Brisbane in round six.

The former Tiger, who had been in brilliant form leading into the Lions game, ran laps while the main group went through drills on Wednesday morning.

"He hasn't had a setback, it's just taking a little bit longer (to get right)," Cameron said.

"He's going to play some sort of footy against Essendon or the week after against Adelaide.

"[I would] have liked it to recover quicker but, in saying that, you've got to be a bit more conservative with a guy that has history of tendon issues, although they've been in his calf."

Cameron revealed that the Giants were constantly reviewing their strength and conditioning programs, and the club had recently asked its academy director, and highly regarded high-performance manager John Quinn to look into their injury toll.

Quinn has previously worked with Essendon, the Socceroos and India's cricket team.

"He's a really good person who has worked in high performance (departments) all his life," Cameron said.

"We've engaged John to put a fresh set of eyes over our program to look at why we're sustaining some of these injuries.

"John might be able to pick out some things that we might be doing rightly or wrongly, and I think that's the sign of a footy club that is open to checking out spots that we might not be covering off on.

"Even though a lot of our injuries can be put down to bad luck, there's always something you can improve in your program."