Free-agency series: Running backs

This is seventh in a 10-part series breaking down the Cowboys' free-agency needs, position by position:

Running backs

Who’s on the roster: DeMarco Murray, Phillip Tanner, Lance Dunbar, Lawrence Vickers

Analysis: If Murray can stay healthy, the Cowboys have a legitimate lead horse. But that’s a huge if after injuries marred his first two NFL seasons. The Cowboys must acquire a backup capable of carrying the load if Murray goes down. Team executive vice president Stephen Jones is on record with the opinion that Tanner and Dunbar, a couple of undrafted backs with local roots, are No. 3 RB types. The Cowboys could also make a change at fullback if they can find a cheaper and/or more effective alternative than Vickers, who was a disappointment after signing as a free agent last offseason.

NFL free agents of interest: Steven Jackson, Reggie Bush, Rashard Mendenhall, Ahmad Bradshaw, Cedric Benson, Michael Turner, Felix Jones.

Need meter: 6. It’d be ironic if Jackson or Mendenhall came to the Cowboys in free agency, considering the controversy when the Cowboys passed on them to pick other backs in the draft. That, however, is extremely unlikely. The return of Jones, the Cowboys’ first-round bust from 2008, as a stopgap backup is more likely if he can’t find an attractive offer in the free-agency market. But there are plenty of recent examples of mid- to late-round backs playing major roles as rookies. It makes sense for the Cowboys to go that route to address their need.