James' agent said on Twitter that his client asked to be released.
James was selected in the second round of the 2012 NFL draft after leading the nation in rushing yards per game at the University of Oregon.
The 49ers used James primarily as a kickoff and punt returner. He carried the ball 27 times in four games as a rookie and 12 times in ten games in 2013. Frank Gore and Kendall Hunter were the team's primary running backs.
The move leaves the 49ers with two running backs on their active roster. Kendall Gaskins is on the practice squad, and Marcus Lattimore is on the reserve/non-football injury list.
- Dan Gartland