to wear jersey numbers between 40 and 49. Named for Bosworth, who unsuccessfully sued the NFL, and had himself listed as a safety, to be allowed to wear the number 44 as a linebacker, the rule was passed long after Bosworth's retirement. Bronko Nagurski rule: Enacted in 1933, forward passing became legal from anywhere behind the line of scrimmage. Enacted in response to a controversial call in the 1932 NFL Playoff Game, in which Nagurski completed a two-yard pass to Red Grange for the Chicago Bears' winning touchdown. The rule at the time mandated that a forward pass had to be thrown from at least five yards behind the line of scrimmage. Nagurski appeared to have not dropped back five yards before passing to Grange, but the touchdown stood. Calvin Johnson rule: A receiver must maintain possession of the football throughout the completion of the play. This was more precisely a clarification of the existing rules regarding catches, made in 2010 in response to a play by Calvin Johnson, who made a falling catch in the end zone, and placed the ball on the ground soon after he hit the ground and before standing up. This was ruled incomplete upon review, and upheld, though it generated discussion about what constituted a catch. Carson Palmer rule: A rushing defensive player won't be allowed to forcibly hit a quarterback below the knees, unless they are blocked into. Enacted in the 2006 NFL season after Bengals quarterback Carson Palmer was injured in the 2005 AFC Wild Card game after he was hit below by Steelers defender Kimo von Oelhoffen, as well as similar injuries to the Steelers' Ben Roethlisberger and the Bucs' Brian Griese. Dave Casper rule: See the "Ken Stabler" rule. Deacon Jones rule: No head-slapping. Enacted in 1977 in response to the defensive end's frequently used technique against opponents. Deion Sanders rule: Player salary rule which correlates a contract's signing bonus with its yearly salary. Enacted after Sanders signed with the Dallas Cowboys in 1995 for a minimum salary and a $13 million signing bonus. (There is also a college football rule with this nickname.) Ed Hochuli rule: Instant replay can be used to determine whether a loose ball from a passer is definitely a fumble or an incomplete pass. This was enacted in 2009 in response to a play in the San Diego Chargers – Denver Broncos Week 2 regular