The NFL is investigating whether the New England Patriots intentionally deflated footballs during their victory over the Indianapolis Colts in Sunday's rain-soaked AFC Championship Game.

A league spokesman confirmed the investigation, which was first reported Sunday by television station WTHR in Indianapolis, to ESPN on Monday morning.

An underinflated football could be easier to grip and catch. NFL rules stipulate that footballs must be inflated between 12.5 and 13.5 pounds per square inch and weigh between 14 and 15 ounces.