We may have covered this, so if we did just link to the thread I missed.
9-1-6-a-3 says, "Players not covered in paragraph 1 (above) may not block below the waist toward the original position of the ball at the snap until the ball carrier is clearly beyond the neutral zone." (Para 1 defines unrestricted players.)
To me, that says unrestricted players may bbw toward the original position of the ball even if outside the tackle box. If you disagree, why would the rules specify who can not do something, leave out someone but still suggest that those left out can't do it either?
However, Redding's BBW FAQ says, "The crackback block is a block below the waist directed toward the line that runs lengthwise through the original position of the ball at the snap. This block is illegal unless the ball carrier is clearly beyond the neutral zone." Nothing about restricted/unrestricted even though the rule talking about crackbacks (above) DOES mention (and seem to exclude) unrestricted players. (Edit: Redding MAY be assuming everyone understands crackback to mean a player who is lined up clearly outside the tackles and comes back in -- hence an unrestricted player).
Saw a play last night where an unrestricted back comes out to the area around where the slot receiver would line up and BBW against a defender. It was a 10-2 block and it was a pass caught behind the NZ. The block sprang the runner.
Legal or illegal and why?