Edwards, who played his 300th game in yellow and black last week, has been ruled out of action due to a back injury.
The 33-year-old was initially listed as 'managed' in Richmond's confirmed changes for Round 21, with the three-time premiership Tiger joining defender Dylan Grimes (hamstring) in being omitted from Damien Hardwick's side.
Jason Castagna has come into our squad of 26 for tomorrow night’s clash with Port Adelaide, replacing Shane Edwards (back) as an emergency.
— Richmond FC 🐯 (@Richmond_FC) August 5, 2022
A win over the Power will see the Tigers strengthen their bid for a finals finish in 2022, currently placed two premiership points outside of the finals frame with three matches remaining in the home and away season.