The move comes mere hours before New England kicks off the 2017 season against the Kansas City Chiefs at Gillette Stadium.
Mitchell, 24, has been dealing with a knee issue that limited him throughout training camp. He participated in just one preseason game.
The second-year pro could be eligible for one of the Patriots' two IR-return designations after sitting out at least eight weeks.
Coupled with Julian Edelman's season-ending knee injury, Tom Brady's receiving corps is completely remade heading into 2017. Brandin Cooks and Chris Hogan lead the depth chart, with Danny Amendola and Dorsett battling for the third wideout duties. New England also added pass-catching tight end Dwayne Allen to go along with Rob Gronkowski. We expect the Pats' bevy of running backs -- James White, Dion Lewis and Rex Burkhead -- to play key roles as pass catchers this season.