If we learned anything about NFL running backs this off-season, it's that they are highly replaceable.
That's how franchises seem to view them, at least, with the Dallas Cowboys allowing their single-season rushing leader, DeMarco Murray, to slip away to NFC East rival Philadelphia; San Francisco parting ways with offensive fixture Frank Gore, and Super Bowl champion New England bidding adieu to both Shane Vereen and Stevan Ridley.
On a grand scale, we witnessed a backfield in motion.
Here, in alphabetical order, are the displaced dozen:
REGGIE BUSH (from Detroit to San Francisco): After rolling up 1,006 yards for Detroit in 2013, Bush ran for 297 in 11 games last season and the Lions released him.