GREATER Western Sydney has received a shock with young star Jacob Hopper set to miss six weeks with a back injury.

The Giants' bad luck hasn't stopped there either, with co-captain Phil Davis (calf) and Matt Buntine (hamstring) both ruled out for 2-3 weeks after being injured in the side's 62-point win over Carlton at Spotless Stadium on Saturday.

Hopper was managed and missed the game against the Blues, but after undergoing a check-up over the weekend, it was discovered he has a stress fracture in his lower back.

The 19-year-old earned himself a NAB Rising Star nomination after a stunning 32-possession debut in round eight against Gold Coast.

Despite some solid form, Hopper has struggled to reach that level again and GWS conditioning staff decided last week was the perfect time to rest him after six straight games at senior level.

David Joyce, Giants' head of athletic performance, said the injury to Hopper came out of the blue.

"Jacob (Hopper) had some discomfort in his back and due to the nature of the issue and his history, he underwent scans that revealed an incomplete stress injury," he said.

"This is disappointing news as Jacob has made a great start to his AFL career this season but due to his age and the stage of his career, we'll be taking an aggressively cautious approach.

"We're pleased that we caught the issue early and we are confident that with conservative management and rehabilitation, he'll be back playing football later in the season."

The loss of Davis and Buntine will further test the GWS backline, with tall defenders Caleb Marchbank (ankle), Aidan Corr (ankle), and Tim Mohr (hamstring) also on the injured list.

Marchbank and Mohr are expected to resume in the NEAFL after this week's bye, but Corr is struggling to overcome the injury he suffered in the Giants' round three loss to the Sydney Swans.

GWS takes on Collingwood at home in round 16, with Joel Patfull and Nick Haynes the only regular key defensive options likely to be available to coach Leon Cameron.

Power forward Jon Patton replaced Davis in defence against the Blues and could make the permanent move down back, with the unlucky Adam Tomlinson another potential replacement.

In better news for the Giants, skillful forward Devon Smith (knee) and small defender Adam Kennedy (shoulder) made a successful return in the reserves last week, with Will Hoskin-Elliott set to play in the NEAFL after the bye.