The western was shot in 1993, the same year the actor died of a drug overdose, but a rights battle left it unreleased.
Lionsgate is planning a VOD release of Dark Blood after it was sold at the Cannes Film Festival by Cinemavault.
About 80 percent of the film was shot when Phoenix died and the rights of the unfinished movie were then controlled by its insurance company. Director and co-writer George Sluizer took control of the rights two days later.
It "laid in my care for many years waiting for something to happen with it. I was making other films at the time and it was safe," Sluizer said.