Tom Brady: I did not alter the footballs

New England Patriots quarterback Tom Brady denied altering last Sunday's game balls in anyway.

In a Thursday news conference Brady said he did not think he was a cheater, explaining he "would never do anything outside the rules of play," nor would he ever ask someone to do something against those rules. He stated categorically that he has never knowingly played with a football deflated below NFL-mandated specifications, and that his team won Sunday's game "fair and square."

"I believe in fair play and I respect the league, and everything they're doing to try to create a very competitive playing field for all the NFL teams." Brady also said that "every team is trying to do the best they can to win every week."

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Underinflated balls are easier to throw and catch, especially in bad weather, and it was raining during Sunday's game, which sent the Pats to the Super Bowl.

The Foxboro, Massachusetts-based team came under fire following that 45-7 rout of the Indianapolis Colts after ESPN reported that 11 of 12 game balls used by the Patriots were underinflated by about 2 pounds.

Responding to a question about a previous statement that he prefers underinflated balls, Brady said he likes the balls at 12.5 psi (within the league-allowed limit)—he said that provides him "a perfect grip for the football."

Tom Brady of the New England Patriots against the Indianapolis Colts during the 2015 AFC championship game, Jan. 18, 2015 in Foxboro, Mass.
Getty Images
Tom Brady of the New England Patriots against the Indianapolis Colts during the 2015 AFC championship game, Jan. 18, 2015 in Foxboro, Mass.

Despite this supposed benefit, Brady said that he did not notice anything strange about the footballs during the game.

Brady did not offer any theories as to how the balls could have been deflated, saying, "Everyone is obviously trying to figure out what happened," and that he was "as surprised as anybody."

"I have no knowledge of anything—I have no knowledge of any wrongdoing of any," Brady said before being cut off by a reporter's question, later adding: "I don't know what happened over the course of the process with the footballs. I was preparing for my own job and doing what I needed to do."

He later said he thinks many people have more information on the matter than he does, and that he also has questions.

Brady explained that he has a pregame process that sees him pick out the footballs he wants to use.

"Our equipment guys do a great job of breaking the balls in," he said. "When I picked 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 them, taking any air out. To me those balls are perfect."

Brady said he may have missed an underinflated ball because he doesn't actually apply much force when he is testing them out before the game.

"I'm not squeezing the balls," the star quarterback said. "That's not part of my process: I grab it, I feel the lace, I feel the leather, I feel the tack on the ball, that's really what you go for."

Brady said he thought that many quarterbacks go through a similar process.

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Patriots coach Bill Belichick said earlier Thursday he was surprised to learn that footballs used by his victorious Patriots for the AFC championship game were deflated.

Belichick said the team has been cooperating with the National Football League's investigation.

"I've never touched a game ball, and was completely unaware of what was going on until Monday morning," he said at a news conference. "I was shocked to learn about the football's situation."

Brady said NFL representatives have not spoken with him yet about the matter, but "they may."

He did say, however, that he would not advocate for the league cracking down on team's supplying their own balls. This process, allows for quarterbacks to be comfortable during the game, Brady said.

"Everybody has a preference: Some guys like them round, and some guys like them thin, some guys like them tacky, some guys like them brand new, some guys like old balls," he said. "I mean, they're all different. And it's leather, and every batch comes—they're different. So you got to feel them, and you try to go out and you try to use the ones that you like the best."

Disclosure: CNBC's sister company NBC Sports broadcasts the Super Bowl.