By Bill Bradley, contributing editor
Editor's note: This is the fourth of five capsules explaining the NFL's new player-safety rules that were passed at last week's Annual Meeting.
THURSDAY: The expansion of chop blocks.
Who: Offensive blockers.
What: Makes it illegal for a back to chop a defensive player engaged above the waist by another offensive player outside the area originally occupied by the tight end.
When: All running plays.
Where: A chop block is a block by the offense in which one offensive player (designated as A1 for purposes of this rule) blocks a defensive player in the area of the thigh or lower while another offensive player (A2) engages that same defensive player above the waist.
How will be it be enforced: A 15-yard penalty for unnecessary roughness.
Reaction: "The committee, Dean (Blandino) brought to our attention that there is a note in there where it is permissible by rule for a running back to line up in the backfield when the ball is snapped and after the ball is snapped go outside the tackle box and block low when a defensive player is engaged high. We don’t think there is a place for that in the game nor do we think we can find an example of it, but it’s kind of a rule clean-up there." -- St. Louis Rams coach Jeff Fisher, who is a member of the NFL Competition Committee.