The Tigers have confirmed a late change to their squad for Saturday night's clash with Port Adelaide, with veteran Shane Edwards removed from Richmond's list of emergencies for the match.

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.

Small forward Jason Castagna has been named in Edwards' place among the emergencies, joining Rhyan Mansell, Thomson Dow and Ivan Soldo.

Young defender Josh Gibcus was the sole inclusion to face the Power, with Round 20 medical sub Maurice Rioli holding a spot in the senior side after replacing Grimes mid-game last Sunday.

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.

Port Adelaide will host Richmond at Adelaide Oval on Saturday night, with the match to commence at 7:40pm (AEST).