It is illegal for any player to put adhesive or slippery substances such as the product “stickum” on his body, equipment or uniform. This rule is known as both the “Lester Hayes Rule” and the “Fred Biletnikoff Rule” since both players were notorious for using sticky substances to make it easier for them to intercept/catch passes.
An offensive player who comes into the game wearing an illegal number for the position he takes must report to the referee before the start of the next play.
The penalty for illegal use of hands, arms, or body (including holding) is reduced from 15 yards to 10 yards.
The penalty for intentional grounding is modified: loss of down and 10 yards penalty from the previous spot, or if the foul occurs more than 10 yards from the line of scrimmage, loss of down at the spot of the foul.
Officials began wearing numbers 21 through 25 within their position groups after going no higher than number 20 in 1979 and 1980.
July 1, 1981: Linebacker Rusty Chambers, the Miami Dolphins leading tackler in 1978 and 1979, died in an automobile accident. 
The Cincinnati Bengals made significant modifications to their uniforms for the first time since the team's debut in 1968, discontinuing the design similar to the Cleveland Browns' jerseys. Orange and black tiger stripes were added to the jerseys and pants. Black tiger stripes were also added to the orange helmets.
The Dallas Cowboys adopted a new blue jersey which was darker than its predecessors and featured silver numbers. The Cowboys wore this blue jersey through 1994.
The Houston Oilers resumed wearing blue pants with their white jerseys.
This was the fourth and final year under the league's broadcast contracts with ABC, CBS, and NBC to televise Monday Night Football, the NFC package, and the AFC package, respectively. The league then negotiated to have all three networks renew their deals for another five years.
John Madden became the lead color commentator for CBS, replacing Tom Brookshier who moved into a play-by-play role. However CBS Sports executives debated on whether Madden should be paired with incumbent lead play-by-play announcer Pat Summerall or should #2 announcer Vin Scully be promoted to the role. To resolve the situation, both Scully and Summerall were paired with Madden in four-week stretches. Scully was paired with Madden during the first four weeks of the season while Summerall was primarily covering the US Open Tennis Championships. Then Summerall called games with Madden while Scully covered the Major League Baseball playoffs for CBS Radio. After the eighth week of the NFL season, CBS Sports executives decided that Summerall had better chemistry with Madden than Scully did. Scully was later assigned as a consolation prize the NFC Championship Game. After the season, he would move to NBC to cover Major League Baseball and golf, but he decided to never call NFL games again.