GREATER Western Sydney has given Collingwood discard Lachie Keeffe an AFL lifeline, signing the key defender as a delisted free agent.

AFL.com.au understands Keeffe has committed to the Giants on a one-year deal, adding to the club's tall defensive stocks behind co-captain Phil Davis, Nick Haynes and Aidan Corr.

GWS general manager of football Wayne Campbell said the versatile Keeffe would also provide ruck support for Rory Lobb and Dawson Simpson.

"Lachie can play as a tall defender or forward, but given his height and the retirements of Shane Mumford and Tom Downie, we see that he can provide us some coverage in the ruck, too," Campbell said.

"He was a popular member of the Collingwood Football Club and we have no doubt he will fit in to our group here.

"Lachie has developed a lot as a footballer in his time in the AFL and we look forward to that continuing at the Giants in 2018."

The 27-year-old Queenslander last featured at AFL level three years ago, when he played a career-high 18 of his 40 matches and looked a major part of the Magpies' long-term plans.

But Keeffe and ex-Magpies teammate Josh Thomas received backdated two-year suspensions from WADA for testing positive to banned drug clenbuterol in the 2015 pre-season.

Check out all the retirements and delistings

Thomas managed nine AFL games in his comeback season and scored a new one-year contract, whereas Keeffe languished in the VFL, kicking 15 goals in 19 matches playing mostly as a ruck-forward.

Keeffe, who stands 204cm and weighs 101kg, told SEN in October after Collingwood delisted him that he played his best football as a defender.

"It'd be in the backline I'd say, that'd be first and foremost," he said of where he would best serve another club.

"That's where I feel I've played my best footy and hopefully I can get a crack and show my wares next year."

The Brisbane Lions drafted his 21-year-old sister, Jessy, in this year's NAB AFL Women's Draft.