Ubisoft marketing executive Tony Key revealed the news to IGN, saying, "Rainbow 6 got caught in the transition of going to next-gen and essentially we're figuring out 'well, are we making the right game for the right hardware systems?'"
Rainbow Six: Patriots was previously targeted to launch in 2013, though a new release window was not provided. The Xbox One and PlayStation 4 launch later this year.
Earlier this week, Ubisoft Montreal CEO Yannis Mallat explained the game's E3 absence, telling media that the title "has a place in the studio," but would not say more.
Most recently, the title was pulled from the GameStop database.
Developed by Ubisoft Montreal with assistance from Ubisoft Toronto and Red Storm, Rainbow 6: Patriots will follow the counterterrorism Team Rainbow squad as it tries to put down a group of American insurgents known as the True Patriots. As players look to suppress the True Patriots' budding revolution, they will be faced with "tough ethical decisions," according to Ubisoft.