Geelong will be without star Tom Stewart for Thursday's qualifying final against Port Adelaide.

Stewart carried a minor hamstring concern into the pre-finals bye but was cleared to play by the club less than a week ago, with the Cats stating illness as the reason for Stewart's absence.

The veteran defender played less than half a game in Round 24 against West Coast due to hamstring awareness, with coach Chris Scott and the Cats having since stated the 31-year-old would be ready to face the Power.

Stewart won't be named to face Port Adelaide, with Geelong to make a late change for their first final.

Stewart ventured to Adelaide a day prior to his teammates and has pushed his case to be cleared to play, however a late change now looms for the Kardinia Park club after the All-Australian woke up unwell.

The Cats can hope Stewart will be ready for their subsequent September showing, which could be a semi-final against either Hawthorn or the Western Bulldogs next week. A win over the Power would mean the Cats are afford a week's rest before a home preliminary final.

Geelong named an unchanged lineup on Wednesday night, with Sam De Koning, Gary Rohan and Oisin Mullin named as the emergencies on standby for Scott.

Port Adelaide swung a pair of changes, with veteran Charlie Dixon and ex-Cat Quinton Narkle coming into Ken Hinkley's side in place of Kane Farrell (hamstring) and Dante Visentini (omitted).

Geelong and Port Adelaide will name their final teams and tactical subs at 6:40pm (AEST) on Thursday.