GREATER Western Sydney coach Leon Cameron is confident his club's poor run of injuries this year is nothing more than bad luck.

The Giants made three forced changes for Saturday's clash with Collingwood at Spotless Stadium, with defenders Matt Buntine (hamstring) and Nathan Wilson (groin), joining star midfielder Ryan Griffen (hamstring) in the rehabilitation group.

Griffen has already missed a large chunk of the season after injuring his back following the round five win over St Kilda.

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Cameron's stocks have been tested all season with Aidan Corr (ankle), Caleb Marchbank (ankle), Tim Mohr (hamstring), Nick Haynes (groin) and Phil Davis (hamstring) missing multiple games, while forwards Devon Smith (knee) and Will Hoskin-Elliott (quad and hamstring) have played little part in 2016.

Young forward Jarrod Pickett (foot) has already been ruled out for the season, while Rising Star nominee Jacob Hopper (back) is expected to miss at least six weeks after playing six games in his debut year.

As part of last week's bye round, GWS conducted a wide-ranging review of every aspect of the club, and Cameron said the Giants' strength and conditioning program wasn’t to blame for his missing players. 

"It's always a tough question to ask," Cameron said.

"Are you doing everything right in terms of your weights, your training, your load? 

"There's no doubt we've developed into a better team this year, so are we exerting more energy on game day to do that, thus do we need to back off during the week? 

"Every day, every week you analyse what you're trying to do.

"I mean 80 per cent of the time these injuries just happen in footy, they're contact injuries.

"There's some where you say what if we'd done this better, but I'm really proud of our program led by (head of athletic performance) David Joyce.

"We think it's in really good shape - we think we've had a lot of unlucky injuries and hopefully that luck can turn in the back half of the year."

The better news for the Giants is that Marchbank, Mohr and Hoskin-Elliott will return through the NEAFL on Saturday, while Davis has been cleared to play the Magpies after coming off during the first half of his side's win over Carlton in round 14 with a calf issue. 

The co-captain completed the club's main training session on Wednesday and pulled up well, and got through a light hit-out on Friday without any issues. 

Davis will be an important player for GWS against a Collingwood side boasting three tall forwards in Travis Cloke, Darcy Moor, and the recalled Jessie White, with veteran Joel Patfull to provide support, and Jon Patton and Adam Tomlinson likely to share dual roles playing at both ends of the ground.

Tomlinson has struggled to cement a spot in Cameron's 22 this season and returns to the side for the third time, while Patton has shown composure in defence filling in for the likes of Davis and Marchbank, as well as playing as a loose man at different stages.

"I'm really rapt with their growth as players," Cameron said. 

"They can play multiple positions and when you get that, it gives you more flexibility.

"There's no doubt adding Adam (Tomlinson), his running ability and ability to defend, but also his ability to play up forward is a good result for us this week."