Not true.
As a poster mentioned in another thread, the success rate for RBs drafted on day 3 is around 10%.
That means that outside of the first 3 rounds, 90% of running backs drafted are busts and wash out of the league.
So, if a team does not draft a RB in the first 3 rounds, the team pretty much is ignoring that position unless you think a 10% success rate is an acceptable risk.
Look at it this way my friend, do you really think the Cowboys would have practically announced tonight they are bringing Zeke back if they legitamately thought there were starting caliber RBs still available in this draft? They obviously are aware of the 10% success rate and are signing Zeke to cover themselves. Sure they might draft a RB on day 3, but they are not depending on that day 3 RB. If he happens to be in the 10% that make it, great. If he is not, then they are covered with Zeke.