PARIS (AP) Scuffed balls, scratched balls, balls switched mid-game. Ball-doctoring isn't only an issue for the NFL, which is investigating a report that the New England Patriots used underinflated footballs in the AFC championship game while beating the Indianapolis Colts 45-7.
A look at dirty tricks in other ball sports:
CRICKET: Ball-tampering is so common in cricket that some of the sport's most famous names have argued it should be legalized.
Spitting sugary saliva on the ball, gouging at its leather covering with fingernails or biting it, picking at its seams, scuffing it with dirt, bottle tops or sandpaper are some of the ploys used by teams over the years to alter the bounce of the ball and flight through the air to make it harder for batsmen to hit.
In a 2010 interview with The Associated Press, former Pakistan bowler Sarfraz Nawaz said some cricketers even ''put glue on their trousers and shirt, and then it goes hard and scuffs the ball'' when they rub it against their doctored clothes.
In a more recent example, South Africa's Faf du Plessis was fined half his match fee in 2013 after he was caught on camera rubbing the ball on the zipper of his trouser pocket. The umpires changed the ball and, in an extremely rare punishment, awarded Pakistan five penalty runs.
BASEBALL: Nippon Professional Baseball Commissioner Ryozo Kato resigned in 2013 to take responsibility after the Japanese league's official ball was made to livelier - it would fly farther after being hit - without his knowing. Major League Baseball has outlawed spitballs since 1920, and pitchers have been repeatedly suspended for using pine tar and emery boards to alter the ball.
TENNIS: At the 2013 Madrid Open, Anabel Medina Garrigues was filmed furiously scuffing new balls by rubbing them hard one after the other against her racket strings, apparently to make them slower and take some sting out of the game of opponent Serena Williams.
Williams won the match. Asked again this week about the incident, Williams said she didn't realize at the time what the Spaniard was doing. ''At the end of the day, whether the ball was fluffy or slow or fast, (the result) I think really depended on what I was able to do and how I was able to play.''
In a statement, the WTA said: ''Had the umpire witnessed the scuffing of the balls, the umpire would have instructed the player to stop.''
''If the player did not stop, it could have led to a code violation,'' the WTA added.
RUGBY: At the 2011 World Cup, England suspended two coaches for illegally switching balls during a 67-3 victory against Romania.
England's kicker, Jonny Wilkinson, was unhappy with what he felt were substandard match balls. England got into such a fret about his kicking problems that two support coaches swapped balls for two of Wilkinson's place kicks after tries were scored. The coaches were subsequently banned for one match each. Unless it is damaged, the ball used to score a try must also be used for the subsequent kick for two extra points.
In his autobiography, Wilkinson claimed the match balls veered right.
''The organizers claim that all the balls are the same, but they're not,'' Wilkinson said. ''It's not exactly surprising that I wouldn't want a ball that flies miles from where it's supposed to.''
OTHER SPORTS: Badminton's code of conduct bars players from ''deliberately tampering with the shuttle to affect its flight or speed.''
In table tennis, players have tampered with their rackets to get more grip, spin and speed on the ball, applying banned racket-enhancing substances that go by various names - speed glue, booster or tuner.
In Premier League soccer, supplier Nike provides each team with 120 match balls for each season. One ball is used per game and match officials check before kickoff that it is correctly inflated. Players can ask the referee to look at the ball and have it replaced if they believe it is incorrectly inflated.