http://central.sonsofsamhorn.net/nfl/the-anatomy-of-a-blocked-punt/
Blocked punts are among the rarest plays in the NFL, with only 12 occurring league-wide in 2013. However, opening weekend this year saw three punts blocked, leading many to wonder whether it was just an aberration and a quirk of the sport, or the sign of a trend spawned by any changes in the game.
In fact, there were no major offseason rule alterations that would lead to an adjustment in punt-blocking strategy. This suggests it was simply an odd early-season cluster of blocks, and that the collective outcomes of punt attempts will likely regress to the mean over the course of the year. A video review of one of these plays readily reveals the culprit as poor punt team execution rather than any new scheme employed by their opponent.