NFL backfield battles may start in the offseason, but many continue into and throughout the regular season.
Some committees have players in clear roles. For instance, James White of the New England Patriots and Theo Riddick of the Detroit Lions are the top pass-catchers in their respective backfields, but they usually don't handle heavy workloads on the ground.
From a fantasy football perspective, players like those are often easier to project on a weekly basis.
It can be frustrating when teams obviously misuse running backs. Chris Carson looked great in Week 1, but the Seattle Seahawks split 14 carries evenly between him and Rashaad Penny.