STAR Greater Western Sydney forward Jeremy Cameron has been ruled out for at least three weeks with a hamstring injury. 

Cameron, who had missed the Giants' losses to Sydney and Richmond in rounds 17 and 18 with hamstring soreness, was recalled to the side last week but struggled through the second half against Fremantle.

The 24-year-old kicked one goal from 16 possessions in the 12-point win over the Dockers at Spotless Stadium, and after the match coach Leon Cameron told the media that his gun forward had copped a knock to his back in the first half.

However scans subsequently revealed he had suffered a hamstring strain.

GWS head of athletic performance David Joyce denied the forward had come back too early.

"There's no reason why he shouldn't have played the game, he was absolutely fine to go into the game," he said. 

"He couldn't have been more prepared. He wasn't rushed back, it was just one of those unfortunate things.

"He got a hit in his back in the second quarter and felt some symptoms down that leg. 

"He tested really well throughout the second half. We went out repeatedly just to check on him and he was fine. We specifically tested him at three-quarter time and he was fine.

"He actually presented worse post match so we scanned him and unfortunately it's revealed he's got a hamstring strain."