The NFL and NFL Players Association reached an agreement on a revised substance-abuse policy.

"With these changes, the NFL and NFLPA once again have the finest and most comprehensive set of drug policies in sports,?" NFL commissioner Roger Goodell said.

"?Our collectively bargained drug policies set the standard for testing protocols and fairness in all of sport," said NFLPA executive director DeMaurice Smith. "We are proud to continue a legacy of protecting the integrity of our game.?"

Key revisions to the program are: