Gilbee, who is owned by over 57,000 DT coaches, left the training track early at the Bulldogs' Wednesday session after hurting his ankle in a tackle.
Bulldogs coach Rodney Eade said, "He got caught in a bit of a tackle. He hurt it again in Darwin, so it has been going on for a few weeks.
"There was some doubt on him anyway. It was the first day that he's trained; he didn't train at all last week, so I suppose there is some doubt now.
"I'll get a further update from the doctor later on, but the doctor did come out and say he's still hopeful he'll be able to play but it's obviously put him in some doubt.
"I'll wait to get an update but we're still hopeful he'll play. We'll certainly give him every chance and certainly name him, but we don't know at this stage."
Those comments suggest Gilbee is unlikely to face the Kangaroos and Eade floated Dylan Addison, Tim Callan or Sam Reid as possible replacements for the defender.