What Makes a Crackback Block Illegal in the NFL?

Aug 23

2 min read

Updated: 7 hours ago

An illegal NFL crackback block can involve prohibited low contact or prohibited contact against a defenseless player. It is not limited to a receiver diving at a defender’s legs.

Part of Football 101. Explore the guide to choose your next topic.

An illegal crackback block is a 15-yard NFL foul that starts with where the blocker lines up and how he moves. In the clearest version, an offensive player begins outside the tackle or in the backfield, moves inward toward the position from which the ball was snapped, and contacts a defender below the waist within five yards of the line of scrimmage.

Rule 12 requires officials to examine where the blocker started, where he moved, where the block occurred and how he made contact. The penalty is fifteen yards.

The alignment, path and area

The block must occur within five yards on either side of the line of scrimmage while the offensive player moves toward the original snap position. The blocker also qualifies through one of these starting conditions:

He was set more than two yards outside an offensive tackle at the snap.
He began in the backfield and moved more than two yards outside a tackle.
He was in the backfield and in motion when the ball was snapped.

That is why replay must show the setup and path rather than only the collision. The general crackback technique guide explains the broader football idea of blocking back toward the formation.

Two kinds of prohibited contact

Within that definition, contact below the waist is prohibited. So is the contact forbidden against a defenseless player under Article 9, including specified forcible head or neck blows, lowered helmet contact and launching.

An above waist block therefore does not automatically avoid the crackback rule itself. The original path and location still matter, and the contact must satisfy all applicable restrictions.

Compare two examples

A slot receiver set four yards outside the tackle folds toward the snap point and strikes a linebacker below the waist near the line. That fits the low contact version.

Change the hit to prohibited forcible head or neck contact against that defender. The fact that the strike was high does not make it a legal crackback.

An inward block with legal contact may be allowed, but can still violate another rule such as holding or an illegal blindside block. The label on the play does not provide an exemption.

Different from a chop or clipping

A chop block involves a prohibited high and low combination by offensive blockers. Clipping addresses contact from behind below the waist against a nonrunner. Crackback has its own alignment and path test.

When a flag appears, rewind to the snap, then judge path, area and contact. The force of the collision alone does not identify the right foul.

Defenders have their own restrictions on cut blocks against eligible receivers, so the legality of a low block also depends on which team is blocking and the play situation.