Coach Mark Thompson said last night that Ablett would struggle to make the side if Lord overcame the virus that forced him out of last week's match against Melbourne.
``Aaron Lord's going to train tonight but he's no certainty to play,'' Thompson said.
``We'd be silly to get rid of Gary if Aaron doesn't play but if Aaron plays Gary might struggle a bit.''
In a blow to the Cats' backline stability vice-captain Brenton Sanderson has been ruled out with a calf injury.
Geelong named an extended seven-man bench to tackle Carlton on Sunday at Colonial Stadium.
Tall forward Cameron Mooney has been named on the bench after a couple of games in the VFL, along with James Rahilly and first-gamer Charlie Gardiner.
Mooney was dropped to the VFL two weeks ago but on Sunday played a leading hand in the side's 45-point win over Sandringham.
``Fantastic second half, strong and powerful,'' Thompson said of Mooney's game.
``He looks like he's enjoying his footy again.''
Gardiner has earned his call up after a string of solid performances in the VFL, including a four-goal haul two weeks ago.
Recruited from the Sandringham Dragons, Gardiner represented Victoria Metro in last year's Under-18 championships and gained All Australian selection.
He finished runner up in Sandringham's best and fairest last year.
Although Carlton has won just the one game this year, Thompson said he wasn't treating the wooden spoon favourites lightly.
``They're travelling badly as far as their win-loss, but I think they've lost five games by between 20 and 30 points which isn't big losses,'' he said.
``It's sort of an indication that they've been able to be competitive and last week was no different.''