Greater Western Sydney forward Rory Lobb has been ruled out of this weekend's clash with West Coast at Spotless Stadium due to groin and hamstring tightness.

Lobb was restricted to light duties at training and trained away from the main group.

The Giants big man took to the training track prior to his teammates and did running drills with fitness coach, David Joyce, before failing to partake in the lights skills session with the rest of the team when they joined him on the track.

Harry Himmelberg has been called into the side as his replacement.

Lobb has played 17 games this season, kicking 17 goals and averaging 8.5 hitouts per game.