(CNN - Jan. 22, 2015) -- New England Patriots quarterback Tom Brady said Thursday he didn't deflate footballs at Sunday's AFC championship game.
"I didn't alter the ball in any way," Brady told reporters.
Brady said he picked the footballs he wanted to use five hours before the game and didn't touch them again until after kickoff.
Brady also said he couldn't tell any difference between the balls in the first and second halves.
Nobody from the NFL has questioned him about football inflation, Brady said. The investigation started Monday and Brady said he didn't know anything about it until a radio interview that morning.
He told Bostion radio station WEEI that the suggestion of the Patriots tampering with footballs in the middle of a game is "ridiculous."
On Thursday, he said, "I was surprised as anybody when I heard Monday morning what was happening."
When a reporter asked Brady whether he was a cheater, the quarterback replied: "I don't believe so. I've always played within the rules."
Asked whether he was confident that no one on his team had done anything wrong, Brady replied: "I have no knowledge of anything. I have no knowledge of any wrongdoing ... I'm very comfortable saying that. I'm very comfortable saying nobody did it, as far as I know."
But he added that he doesn't have all the answers.
"I don't know everything. I also understand that I was in the locker room preparing for a game. I don't know what happened over the course of the process with the footballs. I was preparing for my own job, doing what I needed to do," he said.
He said he was unhappy "Deflategate" had taken the focus away from the Patriots upcoming Super Bowl XLIX against the Seattle Seahawks.
"I don't like the fact that this has taken away from some of the accomplishment of what we've achieved as a team ... hopefully our best is still to come," he said.
Belichick says he never has discussed the issue
Earlier on Thursday, Patriots coach Bill Belichick said he was "shocked" to hear allegations that his team's footballs were under-inflated in violation of NFL rules, a controversy that's cast a shadow over his team as it prepares for Super Bowl.
Belichick denied having any knowledge of the situation, including how the footballs got deflated, and how it may have happened, at last Sunday's AFC championship game, which the Patriots won handily, 45-7, over the Indianapolis Colts.
He said that he's learned more about the football inflation process in three days than he has known or talked about in his 40 years in the league.
"In my entire coaching career, I have never talked to any player (or) staff member about football air pressure," the Patriots coach said at a press conference. "That is not a subject that I have ever brought up. To me, the footballs are approved by the league ... pregame, and we play with what's out there."
Belichick -- one of the most successful head coaches in NFL history with three Super Bowl rings and 211 regular-season wins -- insisted he had no explanation for how the footballs his team used Sunday might have gotten deflated under the NFL-required mandate of between 12.5 and 13.5 pounds per square inch (psi).
But "in the future," Belichick said, New England's game balls will be inflated at high-enough levels -- so closer to 13.5 psi than 12.5 psi, when they may naturally drop to below acceptable levels -- "to account for any possible change during the game."
His comments come days after Indianapolis reporter Bob Kravitz broke the news after Sunday's game that the NFL was looking into whether the Patriots used under-inflated footballs during the AFC championship contest, a story that quickly got the nation's attention and the moniker "Deflategate."
It revolved around the idea that under-inflated footballs -- which, in this case, were used when New England was on offense -- could make them easier to grip, potentially providing a competitive advantage.
ESPN then reported Wednesday, citing NFL sources familiar with a league investigation into the game, that 11 of 12 game balls that the Patriots used on offense were found to be 2 psi under the minimum league requirement.
NFL tight-lipped on its review
For all the talk by unnamed sources, the NFL's official statement on the controversy is succinct: "We are continuing our review and will provide information as soon as possible."
The league regulates game-day footballs, with officials testing and measuring them before opening kickoff. Assuming that happened Sunday and the ESPN report is correct, that would suggest the balls used by the Patriots got deflated during the game -- whether purposefully by an individual or some other way, perhaps tied to the raw, rainy weather that day in Foxboro, Massachusetts.
Belichick didn't shed any light on what happened then. In fact he didn't say much of anything beyond his opening statement, repeating some variation of "I told you everything I know" and "I have no explanation" about 10 times. He did, however, talk some about his philosophy generally.
"My mentality has always been to make things as difficult as possible for players in practice," he said. "So, with regards to footballs, I'm sure that any current or past player of mine would tell you that the balls we practice with are as bad as they can be -- wet, sticky, cold, slippery, however bad we can make them, I make them."
The coach claimed that he didn't have any preferences on footballs, while stating that many quarterbacks and kickers do.
"They're a lot more sensitive to it than I am," he added. "I hear them comment on it from time to time, but I can tell you -- and they will tell you -- that there is never any sympathy whatsoever from me on that subject. Zero."
Patriots' history of winning, controversy
This should be a happy time for the Patriots and their fans. For the 12th time in 14 seasons, the team won its division, the AFC East. And for the sixth time in 14 years -- each one under Belichick -- the squad is heading to pro football's ultimate game.
Instead, New England has found itself on the defensive over the Deflategate reports. In some ways, it's not unlike 2007, when the franchise lost a first-round draft pick and was fined $250,000 for videotaping the signs of New York Jets defensive coaches in violation of league rules.
Belichick got a $500,000 fine himself for that violation, along with the reputation among some as a coach too willing to stretch the rules to help his team. And that has not gone away, with legendary former NFL coach Don Shula referring to him as "Beli-cheat" in a South Florida Sun-Sentinel story -- one that published weeks before the latest incident.
But Belichick also has many admirers among players and fans, for his football acumen and commitment to excellence.
Still, many of them were at a loss after the ESPN report came out less than two weeks before the Patriots' matchup with the Seattle Seahawks in Glendale, Arizona.
And his critics had another reason to pounce, with some calling for big-time punishments, from docked draft picks to Belichick's suspension for the Super Bowl to a play-over of the Colts game.
Others had fun with it all, including hulking Patriots tight end Rob Gronkowski -- now selling shirts on his website showing him spiking a football after a touchdown and the words, "Warning: Gronking may cause deflation."