The days of workhorse running backs carrying your fantasy team to a championship are over.
Between their situational dependence and blocking dependence, drafting running backs can be tricky. The average running back sees more touches than the average wide receiver. But running backs are much more injury prone.
The prevalence of running back committees makes the few top bell-cow running backs arguably more valuable than any other position. However, the committees also make the difference between the average eighth and 25th best running back much smaller than the same difference in regular season scoring for wide receivers.