"crackback block"

[ajmc]

Originally Posted by CT1

In our state, this would be a legal block as long as he has a chance to make a play. If he's just jogging downfield, it's a foul.

Losing concentration of your surroundings while ACTIVELY PURSUING A PLAY does not render a player "defenseless". Although it may render him "Careless" or even "Clueless" both of which often tend to produce harsh (but legal) consequences.

[Welpe]

A crack back is not defined in the rulebook but I've generally understood it to be a block by a wide receiver blocking back towards the original position of the ball at the snap.

In your case, I'd consider that a "blind side block" and per the definition of a defenseless player, he should be considering defenseless. As long as the player being blocked is not hit illegally (out of the play, block below the waist, helmet contact, targeting, etc) then a blind slide block is still legal.

Originally Posted by ajmc

Losing concentration of your surroundings while ACTIVELY PURSUING A PLAY does not render a player "defenseless".

It certainly can per both the NCAA and NFHS definition. It depends upon how he was blocked and what he was focused on. There is a difference between a player out of the play and one who is defenseless.

[Forksref]

I think the defenseless player is a "you have to be there" judgment. Focus is a key word there. I usually think of the player who is 20 yds behind a long return and get lit up. We've always flagged something like that but the new term "defenseless player" makes us all more aware of potential situations.