Belichick said the Patriots conducted an internal simulation to determine what might have led to the balls being underinflated and concluded the team's preparation of the balls would not have caused them to be under pressure.
"We found that once footballs were on the field, adjusted to climatic conditions … they were down approximately 1.5 [pounds per square inch]," Belichick said. "In this case … we did everything as right as we could. We welcome the league's investigation into this matter."
Belichick said the team prepares all of its balls in a controlled environment inside the team's locker room. He said efforts to create the "right feel" of the ball for the quarterback actually increases the amount of air they put into the ball.
"At no time were any of our footballs prepared outside the locker room or somewhere close to that," Belichick said. "They were not prepared in a heated room."
Belichick also stated his quarterbacks could not tell the difference between legal balls and ones that were underinflated by 1 to 1.5 PSI.
Belichick said the internal investigation into the "Deflate-Gate" controversy has been a learning experience for him.
"It's clear that I don't know very much about this area," he said. "Over the last few days, I've learned a lot more than I ever learned, exponentially more."
However, Belichick emphasized the Patriots never were attempting to skirt the rules by using underinflated balls.
"At no time was there any intent whatsoever to compromise the integrity of the game or to try to gain an advantage," Belichick said. "We try to do everything right. We try to err on the side of caution."