http://www.nfl.com/news/story/9658555 Reviewing the Trent Green late slide, and a few other tidbits. Also covers the rule of the QB protection slide. Pretty interesting stuff. 1. When a runner begins to slide feet-first, a defensive player must pull up and avoid unnecessary contact. Rule 7, Section 4, Article 1 provides that the ball is dead and the down ended when any part of a sliding runner's body, other than his hands or feet, touches the ground. This rule was created in 1985 to provide additional protection for a sliding runner by ending the down prior to contact by a defensive player. Therefore, as our Officiating Department has conveyed to coaches, players, and officials at league meetings and clinics for many years, a sliding quarterback should be treated the same as a runner who has been downed. Though it is not necessary for a defensive player to touch the runner to end the down, this does not mean that all contact by a defender is illegal. If a defender has already committed himself, and the contact is unavoidable, it is not a foul unless the defender makes some other act, such as helmet-to-helmet contact or by driving his forearm into the runner. 2. Quarterbacks who desire to take advantage of the protection provided to a sliding runner are responsible for starting their slide before contact by a defensive player is imminent. After the current rule was passed in 1985, some quarterbacks began using a "late slide." Whereas the rule was intended to provide protection for a quarterback who elects to end a run in order to avoid potentially injurious contact, some quarterbacks sought to gain as many yards as possible before beginning a slide when defenders were already close at hand. In the 1989 Competition Committee Report, the committee addressed this problem and reminded the clubs that the sliding quarterback had the obligation "to make his intentions clear;" if he did not, and waited until the last moment to begin his slide, he put himself "in jeopardy of being tackled like a regular ball carrier."