The surprise decision opens the door for pre-season signing Paddy Cross, who joined the Demons after Steven May's retirement, to make his AFL debut.
A 2021 premiership defender, Rivers had been expected to step into the midfield this season after the departure of star pair Christian Petracca and Clayton Oliver.
But the 24-year-old has fallen out of favour with King after just two games in Melbourne's 1-1 start.
The Demons lost Daniel Turner to a fractured hand in last week's loss to Fremantle and have recalled experienced tall Tom McDonald to take on the Blues at the MCG on Sunday.
McDonald and skipper Max Gawn will both make their 250th appearances for Melbourne.
Carlton, who are coming off a bye, have recalled Francis Evans in place of the omitted Lachlan Fogarty.
Meanwhile, West Coast have recalled first-round draft pick Josh Lindsay for their home clash with Port Adelaide on Sunday after losing impressive pre-season selection Milan Murdock (hamstring) and Harry Edwards (concussion) to injuries.
Harry Schoenberg will make his club debut for the Eagles, while former Fremantle and Gold Coast midfielder Will Brodie will do the same for the Power in familiar surrounds in Perth.
Josh Lai will make his AFL debut and Lachie Jones is back from a hamstring injury, with captain Connor Rozee (hamstring), Todd Marshall (ankle) and Miles Bergman (ankle) out injured.
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