ATLANTA (CNN) — New England Patriots coach Bill Belichick said Thursday that 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 XLIX.

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. "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, having won three Super Bowls and 211 games — insisted Thursday 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 pounds per square inch and 13.5 pounds per square inch.

But "in the future," Belichick said, New England's game balls will be inflated at high-enough 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 under-inflated.

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.

Related:

NFL investigating whether Patriots used deflated footballs

NFL spokesman Brian McCarthy says the NFL is investigating whether the Patriots deflated footballs used in their AFC championship game victory over the Colts.

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.

Yet Belichick also has many admirers among players and fans, for his football acumen and commitment to excellence.

Still, even many of them were at a loss for words 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.

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