1973 NFL season

• The league's jersey numbering system is adopted (players who played in 1972 are grandfathered):
  • 1–19: Quarterbacks and specialists
  • 20–49: Running backs, fullbacks and defensive backs
  • 50–59: Centers and linebackers
  • 60–79: Defensive linemen, guards, and offensive tackles
  • 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).

The system would later be modified throughout the years to increase the available numbers to different positions due to increasing team rosters and teams retiring numbers (see also National Football League uniform numbers § Post-1973 changes ).

• Defensive players cannot jump or stand on a teammate while trying to block a kick (leverage).
• 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, the change of possession occurred on the final play of the first or third quarter, or either team took a timeout immediately; 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.

• For the last time until 1997, the last two unbeaten teams in the league met in Week 7,[1] with the Vikings tipping the Rams 10–9.

• N.Y. Jets finished ahead of Baltimore in the AFC East based on head-to-head sweep (2–0).
• Cincinnati finished ahead of Pittsburgh in the AFC Central based on better conference record (8–3 to Steelers' 7–4).
• Kansas City finished ahead of Denver in the AFC West based on better division record (4–2 to Broncos' 3–2–1).
• Dallas finished ahead of Washington in the NFC East based on better point differential in head-to-head games (13 points).
• San Francisco finished ahead of New Orleans in the NFC West based on better division record (2–4 to Saints' 1–5).

• Baltimore Colts: Howard Schnellenberger was hired as head coach. Don McCafferty was fired after going 1-4 to start the 1972 season. John Sandusky replaced McCafferty, getting the Colts to finish 1972 with a 5–9 record.
• Detroit Lions: Joe Schmidt resigned. Don McCafferty was named as Schmidt's replacement.
• Los Angeles Rams: Tommy Prothro was fired and replaced by Chuck Knox.
• New England Patriots: Chuck Fairbanks joined the team as both head coach and general manager. John Mazur resigned after going 2-7 to start the 1972 season, and Phil Bengtson then served as interim.
• New Orleans Saints: J. D. Roberts was fired midway through the 1973 preseason. John North served as head coach for the rest of the preseason and the 1973 regular season onward.
• Philadelphia Eagles: Ed Khayat was replaced by Mike McCormack.
• St. Louis Cardinals: Bob Hollway was fired and replaced by Don Coryell.

• Houston Oilers: Bill Peterson was fired after the Oilers lost their first five games. Sid Gillman finished out the rest of the season.
• San Diego Chargers: Harland Svare left the team after going 1–6–1. Ron Waller served for the last six games.

Through December 1972, all NFL home games (including championship games and Super Bowls) were blacked-out on television in each team's respective city. The first exception was Super Bowl VII in Los Angeles in January 1973; the league changed their policy to black out home games only if tickets 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 President Richard Nixon — were not able to watch their home team win. NFL commissioner Pete Rozelle refused to lift the blackout, despite a plea from Attorney General Richard Kleindienst, who then suggested that the U.S. 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; it eliminated the blackout of games in the home market so long as the game was sold out by 72 hours before kickoff.[3]

With the new rule, the NFL recorded over one million no-shows by ticketholders to regular season games in 1973.[4] On March 23, 2015, the NFL's owners voted to suspend the blackout rules for 2015, meaning that all games would be televised in their home markets, regardless of ticket sales.[5] The blackout rule has been suspended for every subsequent season through 2022.