New England Patriots quarterback Tom Brady sits on the bench in the final minutes of the fourth quarter against the Denver Broncos in the NFL's AFC Championship football game in Denver, January 19, 2014. REUTERS/Mark Leffingwell (UNITED STATES - Tags: SPORT FOOTBALL)

(Reuters) - The National Football League is investigating whether the New England Patriots used deflated balls in their blowout win over the Indianapolis Colts during Sunday's rain-soaked American Football Conference championship.

NFL spokesman Michael Signora confirmed the investigation on Monday but could not offer further comment when asked by Reuters how many instances are in question and what possible punishment, if any, the Patriots could face.

Patriots head coach Bill Belichik said he did not know anything about the potential issue until Monday.

"We'll cooperate fully with whatever the league wants us to; whatever questions they have for us, whatever they want us to do," Belichik told reporters.

According to a report on the NFL's website, a ball was taken off the field and out of circulation during New England's 45-7 win over the visiting Colts that clinched a berth in the Feb. 1 Super Bowl.

Using a deflated ball is presumably done to help players increase their grip, which could have been an issue during Sunday's game that was played in rainy conditions.

According to the NFL report, Patriots quarterback Tom Brady dismissed the claims as "ridiculous" during his Monday morning appearance on Boston radio station WEEI-FM.

"I think I've heard it all at this point," said Brady, who threw three touchdowns in the win. "That's the last of my worries. I don't even respond to stuff like this."

The report also said that if the NFL confirms deflated footballs were used by New England to gain an advantage during the game, it could cost the team draft picks.

The Patriots are no stranger to controversy having been heavily fined by the NFL and docked a first-round draft pick in 2008 for videotaping an opposing team's defensive coaches' signals during a game.

(Reporting by Frank Pingue in Toronto; Editing by Steve Keating)