Greater Western Sydney star Lachie Whitfield is set to be sidelined for an extended period of time after sustaining a bruised liver.

The 26-year-old suffered the injury on Friday during training after feeling a soreness close to his liver.

GWS chief medical officer Bassam Moses revealed that the injury won't hinder too much on Whitfield's season, but the club will be looking to monitor their gun midfielder on a weekly basis.

“It’s on the lower end of the scale and he’s feeling ok at the moment,” Moses told the club website.

“He hasn’t required hospitalisation but it’s hard to put a timeframe on his recovery at this stage.

“He’ll continue to be monitored closely as the bruising subsides and will be a week-by-week proposition.”

The Giants are to face St Kilda at home on Sunday, March 21 to start their 2021 season.