Today's NFL is pass-driven. Quarterbacks and pass-catchers have become the offensive stars, while defensive backs and pass-rushers have become the most in-demand players on the other side of the ball.
The ground game still has an important place in modern football, but it doesn't look like it once did. Though young running backs such as Ezekiel Elliott, Leonard Fournette and Todd Gurley have recently brought back the concept of the dominant rusher, every-down backs are few and far between.
Most teams employ a committee, each back with his own specialization. During the course of a game, we'll see bruising early-down rushers, pass-catching backs, blocking specialists and even the occasional fullback.