http://www.nfl.com/videos/st-louis-rams/09000d5d823c7a5c/Playbook-Rams-vs-Cardinals

that is flagrant holding, to me.. of course matt millen thought it was a great play (not sure if sarcastically, speaking..)

From http://www.nfl.com/rulebook/useofhands

A defensive player may not tackle or hold an opponent other than a runner. Otherwise, he may use his hands, arms, or body only:

(a) To defend or protect himself against an obstructing opponent.

Exception: An eligible receiver is considered to be an obstructing opponent ONLY to a point five yards beyond the line of scrimmage unless the player who receives the snap clearly demonstrates no further intention to pass the ball. Within this five-yard zone, a defensive player may chuck an eligible player in front of him. A defensive player is allowed to maintain continuous and unbroken contact within the five-yard zone until a point when the receiver is even with the defender. The defensive player cannot use his hands or arms to push from behind, hang onto, or encircle an eligible receiver in a manner that restricts movement as the play develops. Beyond this five-yard limitation, a defender may use his hands or arms ONLY to defend or protect himself against impending contact caused by a receiver. In such reaction, the defender may not contact a receiver who attempts to take a path to evade him.

(b) To push or pull opponent out of the way on line of scrimmage.

© In actual attempt to get at or tackle runner.

(d) To push or pull opponent out of the way in a legal attempt to recover a loose ball.

(e) During a legal block on an opponent who is not an eligible pass receiver.

(f) When legally blocking an eligible pass receiver above the waist