It seems like most of the posters here don't understand clipping. Not only do you have to go below the waist, the defender also had to be engaged with another blocker. So him going below the waist is irrelevant here.
You are describing a chop block. Clipping is different as described below. Didn't look like a clip to me, but it did look like a hold by Escobar.
SECTION 6
CLIPPING
Clipping is blocking an opponent from behind below the waist, provided the opponent is not a runner. It is not clipping if an
opponent turns his back as the block is delivered or about to be delivered.
Note
s:
(1) It is clipping (including in close line play) if an offensive player’s block (legal or illegal) is followed by the blocker rolling up on the side or back of the legs of the defender.
(2) See 12-2-1 for additional interpretations or restrictions concerning clipping in close-line play.
SECTION 2
PERSONAL FOULS
ARTICLE 1
. CLIPPING.
There shall be no clipping against a non-runner. This does not apply to offensive blocking in close-line play where it is legal to clip above the knee(s), but it is illegal to clip at or below the knee(s).
If an offensive player’s block(legal or illegal) is followed by the blocker rolling up on the back or side of the leg(s) of a defender, it is clipping, including in close-line play. Close-line play is that which occurs in an area extending laterally to the position originally occupied by the offensive tackles and longitudinally three yards on either side of the line of scrimmage. See 3-7, close-line play.
Exception:
An offensive lineman may not clip a defender above the knees who, at the snap, is aligned on the line of scrimmage opposite another offensive lineman who is more than one position away, and the defender is responding to the flow of the ball away from the blocker.
Example:
Tackle cannot clip nose tackle on a sweep away.
Note:
If there is a block from the side, or if an opponent turns his back as the block is being made, it is not clipping if the opponent is able to see or ward off the block. Provided the blocker does not roll up on the back or side of the opponent’s leg(s).
(a) When a blocker, who is moving in the same direction as an opponent, initially contacts the opponent on his side, and subsequently contacts the opponent below his waist from behind, it is not clipping if the contact is continuous.
(b) Clipping shall not be called if an official has not observed the blocker’s initial contact with an opponent.