The moves were announced by the Bills on Tuesday, when players began arriving for the start of the team's off-season voluntary conditioning program.
Choice, who was a free agent, enters his sixth NFL season. Buffalo claimed him off waivers in late November 2011. He had 47 carries for 193 yards and a touchdown in 12 games last season playing behind starters C.J. Spiller and Fred Jackson.
Dickerson was used as a pass-catching halfback in former coach Chan Gailey's system last year. The second-year player had nine catches for 117 yards in 2012 after signing with the Bills in May.