season game where, in the final minutes, referee Ed Hochuli ruled that Broncos quarterback Jay Cutler threw an incomplete pass. Replays clearly showed it was a fumble, but the play was previously not reviewable. Emmitt Smith rule: A player cannot remove his helmet while on the field of play, except in the case of obvious medical difficulty. A violation is treated as unsportsmanlike conduct. Enacted in 1997. The Dallas Cowboys running back was the most high-profile player who celebrated in this manner immediately after scoring a touchdown. Fran Tarkenton rule: A line judge was added as the sixth official to ensure that a back was indeed behind the line of scrimmage before throwing a forward pass. Enacted in 1965 in response to Tarkenton, who frequently scrambled around in the backfield from one side to the other. Greg Pruitt rule: Tear-away jerseys became illegal starting in 1979. Pruitt purposely wore flimsy jerseys that ripped apart in the hands of would-be tacklers. Such a jersey was most infamously seen in a 1978 game between the Rams and Oilers in which Earl Campbell's jersey ripped apart after several missed tackles. Hines Ward rule: The blocking rule makes illegal a blindside block if it comes from the blocker's helmet, forearm or shoulder and lands to the head or neck area of the defender. Enacted in 2009 after the Pittsburgh Steelers receiver broke Cincinnati linebacker Keith Rivers's jaw while making such a block during the previous season. Jerome Bettis rule: Enacted in 1999, the rule states all calls for coin flips will occur before the referee tosses the coin in the air, and at least two officials will be present during the coin toss. This is in response to a call considered one of the "worst in history." In a Thanksgiving Day game with the Detroit Lions on November 26, 1998, Bettis was sent out as the Steelers' representative for the overtime coin toss. Bettis appeared to call "tails" while the coin was in the air but referee Phil Luckett declared that Bettis called "heads" and awarded possession to Detroit, who would go on to win the game before Pittsburgh had the chance to have possession. Jim Schwartz rule: Modifying the "no-challenge" rule adopted prior to the season to eliminate the automatic "no-review" penalty when a coach challenges a play that is subject to automatic review by the replay booth (turnovers, scoring plays, and any