GWS midfielder Ryan Griffen will miss the next 3-4 weeks due to a hamstring injury.
Griffen suffered the injury at training last week and subsequently missed last week's match against the Pies, with the club confirming on Tuesday that he could miss up to a month.
Young running defender Nathan Wilson is expected to miss 2-3 weeks due to groin soreness.
Wilson also missed last week's loss to Collingwood, with the Giants confirming the extent of the injury today.
Meanwhile, defender Matt Buntine is still 1-2 weeks away from a return from a hamstring injury, while Aiden Corr is at least a fortnight away from returning from an ankle injury.
The Giants face the Lions at the Gabba on Sunday afternoon at 4.40pm AEST.