James, 24, was taken in the second-round of the 2012 draft, but was unable to carve out a role with the 49ers.
The Dolphins promoted him to their active roster just last week, so there’s a chance they could re-add him to their taxi squad in the coming days.
Last year, the 49ers had James active for just 10 games, which had a lot to do with him being slotted as the No. 4 running back on their depth chart. James wound up playing just 28 snaps this season and totaled 59 yards on 12 carries.