The "neighborhood play" is a colloquial term used to describe the leeway granted to middle infielders with regards to touching second base while in the process of turning a ground-ball double play. Though it is not explicitly mentioned in the rulebook, middle infielders were long able to record an out on the double-play pivot simply by being in the proximity -- or neighborhood -- of the second-base bag. The maneuver had been permitted for safety purposes, as it allowed the pivot man to get out of the way of the oncoming baserunner as quickly as possible.
But via a rule change instituted before the 2016 season, the neighborhood play is now reviewable by instant replay. That means middle infielders must touch the second-base bag while in possession of the ball in order to ensure the out is made on a ground-ball double play. In order to protect the middle infielders, Major League Baseball also amended the sliding rules for baserunners.
History of the rule
The amendments to the sliding rules were implemented after a 2015 season in which a number of middle infielders were injured by sliding baserunners while covering second base. In accordance with the rule change, MLB determined that questionable slides and the neighborhood play would both now be reviewable by instant replay.