So either the NFL is admitting that New England Patriots quarterback Tom Brady didn't do anything wrong, or they're just absolutely clueless about ball pressure.
According to ESPN's Sal Paolantonio, the NFL is concerned about the footballs inflation levels due to the subzero temperatures, and will use the backup footballs for the second half of the game.
Per Sal Paolantonio: Officials in MIN worried about footballs going under 12 PSI; will use backup footballs in 2nd half that've been inside— Aaron Levine (@AaronQ13Fox) January 10, 2016
The league is ridiculous and there are two possible interpretations.
The first is that the league's data over the course of the season has revealed that temperature-related deflation is completely natural and a part of the game. After an offseason of leaks, the fact that the NFL has kept the measurements under wraps implies that the data doesn't help the league. This understanding would completely clear the Patriots from any wrong-doing, so it's likely confirmation of this will never reach the surface.
The other is that the league still doesn't understand how temperature affects the ball pressure and they're just being dumb. The footballs in the 2nd half are going to be affected in pretty much the exact same way as the footballs in the first half. The first half footballs will naturally regain some of their pressure if the officials take them into the locker room to warm up at half time. These are literally the foundational arguments set forth by Exponent and Ted Wells in the science section of the Wells-Pash Report, and the science could still be over the collective head of the NFL offices.
Either way, ball deflation is on the mind of the league and they know that it's a real thing.