(Reuters) - The New England Patriots probably deliberately deflated the footballs to gain an advantage in the AFC title game in January, and quarterback Tom Brady was "at least generally aware" of the scheme, the National Football League said on Wednesday.
NFL Commissioner Roger Goodell said the league would consider possible disciplinary action and what rules, if any, need to be changed.
"At the same time, we will continue our efforts vigorously to protect the integrity of the game," he said.
A 243-page report was released by Ted Wells, an attorney hired by the league to investigate allegations that the Patriots purposely deflated the balls used in their 45-7 victory over the Indianapolis Colts.
"We have concluded that, in connection with the AFC Championship Game, it is more probable than not that New England Patriots personnel participated in violations of the playing rules and were involved in a deliberate effort to circumvent the rules," the report said.
The report also concluded that Brady, a four-time Super Bowl champion and future Hall of Famer, "was at least generally aware" of the arrangement. Brady has previously denied knowledge about the underinflated balls in a scandal known as Deflategate.
Patriots CEO Robert Kraft said he does not agree with the report's findings but would not challenge them.
"While I respect the independent process of the investigation, the time, effort and resources expended to reach this conclusion are incomprehensible to me," Kraft said. "Knowing that there is no real recourse available, fighting the league and extending this debate would prove to be futile."
After routing the Colts in the AFC championship, the Patriots defeated the Seattle Seahawks, 28-24, in the Super Bowl, a feat many believe was tarnished by the scandal.
The NFL has rules on the minimum amount of air that must be in footballs and many believe underinflating them would give a quarterback an advantage in gripping the ball, especially during the chilly conditions like those in the AFC title game.
Jim McNally, a locker room attendant for the Patriots, and John Jastremski, an equipment assistant, likely participated in the plan to release air from the balls after they were examined by the referee, the report concluded.
"To say we are disappointed in (the report's) findings, which do not include any incontrovertible or hard evidence of deliberate deflation of footballs at the AFC championship game, would be a gross understatement," Kraft said.
Reporting by Steve Ginsburg; Editing by Susan Heavey and Bill Trott