What is the rarest penalty called in the NFL?

The NFL’s Rarest Penalty: A Forgotten Rule

Deep in the dusty corners of NFL rulebooks lies one of the game’s most mysterious and seldom-seen penalties: "assisting the runner." While most fans are familiar with flags for holding, pass interference, or defensive offside, this particular infraction has become the stuff of football legend—mostly because it’s almost never called.

Officially, "assisting the runner" occurs when an offensive player helps a ball carrier advance by pushing or pulling them forward. The rule exists to prevent unfair momentum gains, but in practice, it’s nearly extinct. Despite being part of the official rulebook, it hasnt been enforced in an NFL game since 1991—a fact that surprises even longtime referees and coaches.

Why so rare? In the heat of a play, it’s difficult to distinguish between accidental contact and intentional pushing. Plus, the NFL’s emphasis has long been on player safety and flow of the game, making officials hesitant to flag a play for such a minor and subjective violation. As a result, "assisting the runner" survives mostly in trivia, not touchdowns.

Still, it remains a rule in effect, a ghost of the past lurking behind every rush attempt. While no one expects to see a flag for it anytime soon, its mere existence reminds us that football’s history is full of quirks, some of which are preserved only in memory and fine print.