FOXBOROUGH, Mass. - Patriots coach Bill Belichick said Monday he will cooperate with an NFL investigation into whether the Patriots used footballs that were not fully inflated during Sunday’s 45-7 win over the Colts in the AFC Championship Game.

NFL spokesman Michael Signora confirmed to Newsday early Monday morning that the league was looking into the matter, although it is uncertain when the investigation will be completed. NFL rules prohibit teams from underinflating footballs during games.

“We’ll cooperate fully with whatever the league wants us to do, whatever questions they have for us, whatever they want us to do,” Belichick said Monday afternoon during a conference call with reporters.

Belichick said he heard about the report that the footballs may not have been properly inflated Monday morning. “Whatever we need from the league, then that’s what we’ll do.”

On his weekly interview on sports radio WEEI later Monday, Belichick again was asked about using deflated footballs.

“I can’t imagine,” he said. “I really don’t know what to say or know anything about what we’re talking about here. Whatever it is, we’ll cooperate with them the best we can.”

The potential use of underinflated game balls was first reported by Bob Kravitz of WTHR.com two hours after the game. Using underinflated footballs can help quarterbacks and receivers grip the ball better, especially in the rain. It rained during the game and there were occasional downpours.

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Patriots quarterback Tom Brady, in his weekly spot on WEEI, laughed off the suggestion that the Patriots were not using properly inflated game balls. He called the allegations “ridiculous,” adding: “I think I’ve heard it all at this point. That’s the least of my worries. I don’t even respond to stuff like this.”

The game’s result will count, and the Patriots will play the Seahawks in Super Bowl XLIX. If the NFL finds the Patriots used underinflated footballs, it could fine them or remove draft picks.

According to a person familiar with the background of the matter, the Colts first noticed something unusual after an interception by Colts linebacker D’Qwell Jackson in the second quarter. Jackson gave the ball to a member of the Colts' equipment staff, who noticed the ball seemed underinflated and then notified coach Chuck Pagano.

General manager Ryan Grigson was notified in the press box, and he contacted Mike Kensil, NFL director of football operations. Kensil then told the on-field officials at halftime, when the Patriots led 17-7. The Patriots erupted for 21 points in the third quarter, although it is not known if any of the balls were improperly inflated after halftime.

Asked Monday about the balls, Pagano said: “Did not notice, and that’s something for the league to handle. It’s not my place to comment on it.”

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The Colts did not notice any irregularities with the game-day footballs when the teams played in Indianapolis in November.

NFL vice president Greg Aiello had no comment on how the officials learned of the potentially underinflated footballs. NFL’s director of officiating Dean Blandino said on NFL Network that “if something is noticed, it’s not unheard of for a ball to be removed from circulation and then tested during the week for whatever issue there was.”

Blandino did not comment directly on the investigation.

NFL rules require each team to provide 12 in-game footballs that the officiating crew inspects two hours before kickoff. Each team provides its own footballs when its offense is on the field. League rules require that footballs be inflated to between 12.5-13.5 pounds per square inch (PSI) at all times.

This is not the first time the Patriots have been involved in a game-day controversy. In a 2007 game against the Jets, they were accused of taping the Jets’ sideline defensive signals. The NFL determined the Patriots violated NFL rules and made them surrender their 2008 first-round draft pick. The team was fined $250,000 and Belichick was fined $500,000.