Broncos insider Jeff Legwold reports that the team is looking to add a "bigger tailback to share the workload" with Willis McGahee.  Legwold lists Vick Ballard, Jonas Gray, Ronnie Hillman, Doug Martin, and Robert Turbin as potential targets for Denver in the draft.  Martin is a 1st or 2nd-rounder, while the other guys could be had in the middle or late rounds.  The Broncos could also go after free-agents like Mike Tolbert, BenJarvus Green-Ellis, or Brandon Jacobs.  They'll be smart to limit the 30-year-old McGahee's workload this coming season.