Port Adelaide defender Jack Hombsch has been ruled out of Showdown XLII because of injury.

Hombsch suffered a minor medial ligament strain in his right knee late in the final quarter of the Power’s win over Fremantle on Sunday. He's expected to miss 3-4 weeks.

Fellow backman Jasper Pittard (hamstring) will need to pass a fitness test at the club’s main training session on Thursday. Hamish Hartlett, who was a late withdrawal on Sunday because of illness, is available for selection.