60–79: Defensive linemen and offensive linemen other than centers
80–89: Wide receivers and tight ends
Numbers 0, 00, and 90 to 99 are no longer allowed to be issued, even though these numbers were rarely issued anyway (two players wearing 00 at the time, Jim Otto and Ken Burrough, were grandfathered). Numbers 90 to 99 would be allowed again for defensive linemen from 1979 and for linebackers from 1984 in addition to the above-mentioned numbers.
Defensive players cannot jump or stand on a teammate while trying to block a kick.
The clock is to start at the snap following all changes of possession. Previously, the clock started on a change of possession when the ball was spotted ready for play by the referee, except if the ball went out of bounds on the change of possession, there was an incomplete pass on fourth down, or the change of possession occurred on the final play of the first or third quarters; in those cases, the clock started on the snap.
If there is a foul by the offensive team, and it is followed by a change of possession, the period can be extended by one play by the other team.
If the receiving team commits a foul after the ball is kicked, possession will be presumed to have changed; the receiving team keeps the ball.
Up until the 1972 season, all NFL games (including championship games and Super Bowls) were blacked-out on television in each team's home city. In 1973, the league changed their policy to black out games in the team's home city only if tickets to the game had not sold out. This expanded the league's television presence in teams' home cities on gameday.
The policy was put into effect when, in 1972, the Washington Redskins made the playoffs for only the second time in 27 seasons. Because all home games were blacked-out, politicians — including devout football fan PresidentRichard Nixon — were not able to watch their home team win. NFL commissionerPete Rozelle refused to lift the blackout, despite a plea from United States Attorney GeneralRichard Kleindienst. Kleindienst was to suggest that the United States Congress re-evaluate the NFL's antitrust exemption. Rozelle agreed to lift the blackout for Super Bowl VII on an "experimental basis". But Congress intervened before the 1973 season anyway, passing Public Law 93-107, which eliminated the blackout of games in the home market so long as the game was sold out by 72 hours before game time.
Starting in 1970, and until 2002, there were three divisions (Eastern, Central and Western) in each conference. The winners of each division, and a fourth “wild card” team based on the best non-division winner, qualified for the playoffs. The tiebreaker rules were changed to start with head-to-head competition, followed by division records, records against common opponents, and records in conference play.
Note: Prior to the 1975 season, the home teams in the playoffs were decided based on a yearly rotation. Had the 1973 playoffs been seeded, the AFC divisional matchups would have been #3 Oakland at #2 Cincinnati and #4 wild card Pittsburgh at #1 Miami; the NFC matchups would not have changed, although #3 Dallas would have had to travel to #2 Los Angeles, and #1 Minnesota would have had home field for the NFC championship game.