Prior to last season, the NFL changed its Official Playing Rules  in an effort to protect snappers during field goal and extra point attempts by requiring the defender’s helmet to be outside the snapper’s shoulder pads.  This year, the Rule, contained at Rule 7, Section 2, Article 2,  has been amended slightly to apply during punts and require that the defender’s entire body be oustide the snapper’s shoulder pads.

Here is the Rule as it existed for the 2009 season:

During a field-goal attempt or a Kick Try, a Team B player, who is within one yard of the line of scrimmage at the snap, must have his helmet outside the snapper’s shoulder pads.

Here is Rule 7, Section 2, Article 2 for the 2010 season:

During a punt, field-goal attempt, or a Kick Try, a Team B player, who is within one yard of the line of scrimmage at the snap, must have his entire body outside the snapper’s shoulder pads.

The new Rule mentions that it does not apply if the team does not present a kicking formation.