Davies-Uniacke, one of the Kangaroos' prime midfield movers, has been ruled out from Saturday night's MCG fixture because of a heel injury.
The 15th-placed Kangaroos have summoned ex-Fremantle utility Darcy Tucker as a replacement for their fixture against the third-placed Demons.
Melbourne will hand Josh Schache a debut for the club after his move from the Western Bulldogs.
"He has earnt his spot," Melbourne coach Simon Goodwin told reporters on Friday.
"He has come in to our environment and worked really hard on some of the things in his game that he needed to and wanted to.
"He has been able to play some really dominant VFL footy over a number of weeks now, he has been pushing for the last month."
Schache replaces Harrison Petty (concussion) while the Kangaroos have regained co-captain Jy Simpkin from a hand injury and recalled ruck-forward Callum Coleman-Jones.
The Roos won their opening two matches but have since lost four in a row.Â
The past two have been heavy away defeats to the Brisbane Lions (75 points) and Gold Coast (43).
But Goodwin said his Demons remained wary, particularly given forecasts of rain.
"They're a young group that have travelled," Goodwin said of the Kangaroos.
"They get some experience back in their team this week and some high-quality players.
"Their best is on the improve. They're a team that is coming through, they have got a lot of talent and mixed with a bit of experience.
"They're a contest team, they do well at stoppage and it's going to be one of those games where conditions might be a bit slippery.
"So it's going to be a contest-based game and one we will have to be up for because they're pretty good in that phase of the game."
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