The New England Patriots are the target of an NFL investigation involving allegedly under-inflated footballs used during Sunday's rainy AFC Championship game against the Indianapolis Colts.
According to ESPN reporter Chris Mortensen, the league found 11 of the 12 of the balls supplied by the Patriots to be under-inflated.
After a second quarter interception by Colts linebacker D'Qwell Jackson, Indianapolis coaches alerted NFL referees that something felt abnormal with the game footballs.
While the NFL has yet to determine the exact cause, cold and drenching conditions can play a factor into game equipment.
Just like vehicle tires, air pressure within a ball can drop when temperatures drop. Pressure in a football drops on a smaller scale, but it is similarly impacted by cold conditions.
Temperatures at the start of the 6:40 p.m. game were in the low 50s in Foxborough, Massachusetts. As the evening developed, temperatures settled into the upper 40s by the end of the game.
While temperatures for an outdoor venue in mid-January were not severe, a drop in indoor to outdoor temperatures can alter the pressure. When inflated inside warm, climate-controlled conditions, the ball pressure can be impacted by the transition to lower outdoor temperatures and brisk, rainy conditions.
Additionally, showers hit Gillette Stadium and eventually a steadier rain drenched players and fans into the second half of the game.
While weather brings adverse conditions to game situations, referees are required to inspect up to 36 balls provided by the home team for an outdoor venue. An additional dozen new, unopened footballs must be inspected for kicking plays, according to the NFL Rulebook.
It is not yet clear which balls were found to be under-inflated. In Mortensen's report, the NFL discovered 11 home team balls to be under-inflated by 2 pounds each.