In his report released on Wednesday, attorney Ted Wells said the NFL team probably deflated footballs in their 45-7 win over Indianapolis in last season's AFC championship game that put them in the Super Bowl.
The NFL investigated reports that 11 of the Patriots' 12 allotted game footballs were underinflated by two pounds per square inch.
The NFL requires balls to be inflated between 12.5 and 13.5 pounds per square inch. Under league rules, each team provides 12 balls for use on offence. Referees approve the balls more than two hours before game time, then keep the balls until they're turned over to ball handlers provided by home teams just before kickoff.
Patriots head coach Bill Belichick said the balls used by the Patriots offence are inflated to the "12½-pound range" and "any deflation would then take us under that."
"I didn't alter the ball in any way," Brady said during a news conference in January.
"I have a process I go through before every game where I go in and pick the balls — the footballs that I want to use for the game. Our equipment guys do a great job of breaking the balls in. They have a process that they go through.
"When I pick those footballs out, at that point, to me, they're perfect. I don't want anyone touching the balls after that, I don't want anyone rubbing them, putting any air in, taking any air out, to me those balls are perfect and that's what I expect when I'm on the field."
'Generally aware' of violations
This week's report also said Brady, 37, was probably "at least generally aware" of the violations.
Should the league come down hard on the veteran pivot, Brady would be the highest-profile player ever barred in the 96-year history of the NFL.
Brady on Thursday said the team's Super Bowl victory over Seattle was not tainted by the "Deflategate" investigation, but he declined to directly respond to the probe's findings.
"No, absolutely not," Brady said during a speaking engagement at Salem State University when asked if the scandal over deflated footballs raised questions about the team's 28-24 victory over the Seahawks in February.
The Miami Herald has reported the Brady suspension could be for the entire 2015 season.
Reports on Friday in Boston said NFL commissioner Roger Goodell could slap the four-time Super Bowl champion and three-time Super Bowl MVP with a six-to-eight game-suspension.
Obviously, any games Brady misses damages the team's chances to repeat as champion.