Fox won the race to take Mills' spot for Friday night's contest at the SCG after the skipper strained his left hamstring at training last week.
The huge selection call means more finals heartbreak for Swans midfielder Taylor Adams, who was squeezed out of the side by several returning stars this month.
Adams moved to Sydney in search of more midfield minutes this season, having played in Collingwood's losing grand final in 2018 and missed out on last year's premiership with a hamstring injury.
The sights and sounds of Captain's Run on the — Sydney Swans (@sydneyswans) @scg ✔️ ☀️ #Bloods pic.twitter.com/4wvA4cILNASeptember 19, 2024
Port have recalled veteran forward Charlie Dixon to replace Todd Marshall (concussion) and Ryan Burton has overcome a calf problem that kept him out of the semi-final win over Hawthorn.
Burton replaces two-game teenager Will Lorenz, who was the substitute against the Hawks.
Geelong have made just one change to their side to take on Brisbane at the MCG on Saturday, with Stewart back and Sam De Koning overlooked with Tom Hawkins and Cam Guthrie.
Stewart returns from hamstring tightness and illness, which prevented him from playing in the Cats' 84-point hammering of the Power in week one of the finals.
Retiring Irish veteran Zach Tuohy, who was the substitute against Port, is the unlucky player to miss out.
Fellow Irishman Oisin Mullin was a late inclusion when Stewart withdrew from the qualifying final and has held his spot in the side.
Geelong couldn't find room for versatile tall De Koning, who has not played an AFL game since round 21.
A 2022 premiership player, De Koning featured 19 times during the home-and-away season and has had two VFL hit-outs on return from minor knee surgery.
Sam De Koning prepares to put on a fend during the Cats' VFL semi-final against Southport. (Julian Smith/AAP PHOTOS)
Veteran pair Hawkins (foot) and Guthrie (achilles) were also left out despite also returning from injuries through the VFL this month.
Coach Chris Scott said earlier this week the club did not consider the experienced duo "fit and available" to face the Lions.
The door has not yet been closed on Hawkins or Guthrie playing in the grand final, if Geelong qualify.
Brisbane have named an unchanged team from the one that pulled off a remarkable semi-final comeback from 44 points down against GWS last week.
The line-up features 18 players from the side that lost to the Magpies in last year's grand final.
Two-time Brownlow Medal winner Lachie Neale trained well this week and has been named despite ongoing heel pain which had cast some doubt over his availability.
