Bulldogs' assistant coach Paul Williams told the club's website the coaching staff were confident the former Cat could add something to the side against a formidable and undefeated opponent.

"We thought it was a great opportunity for him to come in and play against the Cats," he said on Thursday.

"We know what Nathan brings to our side, he's a great pressure player, an inside mid who can play forward."

As reported earlier in the week, Mulligan will play his first game for the Dogs in what is his fourth year on the club's list.

The 21-year-old has been named at centre half-back and will fill a role in a defence that has been strengthened by the return of Brian Lake last week, and Ryan Hargrave for Saturday.

"We are starting to get a formulation of our back six with Lake, [Dale] Morris and Hargrave finally being in the same team together," Williams said.

"Mulligan comes in and he's a young kid from Queensland who's been getting significant roles in the VFL for Williamstown.

"We're really looking forward to what he might be able to do for us this week.

"He's a quick 197cm backman who really plays his best footy playing on the lead-up players, so he'll get a big job on one of the big key forwards for Geelong."

Jarrad Grant is the fourth inclusion for the Dogs after he kicked four goals for Williamstown last weekend.

Tom Williams has been named at centre half-forward and will perform the role of the second ruckman in the continuing absence of Ben Hudson.

The Dogs will give first-year midfielder Tom Liberatore a rest this week while Sam Reid is out with the two-to-three week hamstring he sustained last Sunday against Hawthorn.

Barry Hall, as predicted on Wednesday by fellow assistant coach Brett Montgomery, has failed to come up from the ankle he "jagged" against the Hawks and will miss.

Defender Lindsay Gilbee, who Montgomery claimed was lucky to get a late reprieve last weekend, has been dropped again.

"He hasn't played to the level we expect, he knows what he needs to do and we expect him to be back in team sooner rather than later," Williams said.

Gilbee was omitted from the side that lost to West Coast in round nine after having just eight touches but was brought into last week's team after Brodie Moles and Hargrave were forced to withdraw on Saturday with injury.

He failed to make an impact against the Hawks and again collected the ball just eight times.

Williams said the clash with the unbeaten Cats, who could become the only team in history to win 10 or more games 14 times with a victory, was a big challenge for the Dogs but believed they were up to it.

"It's a huge game for us this week. We know the Cats are undefeated but it doesn't mean anything for us," he said.

"We really want to bring our style, our effort, and if we do that, we give ourselves a chance against any side."