During last season, especially the ALCS, several plays were deemed to be considered controversial on whether or not balls were ruled home runs. During a game in the annual interleague Subway Series between the Mets and the Yankees at Yankee Stadium, a home run was taken away and ruled a ground rule double. This led to discussions about introducing instant replay to Baseball games, especially on balls that are ruled fair or foul and home runs. In August, all 30 parks have been wired to send feeds similar to a video goal judge in the NHL, where all video feeds are sent to a central control room at Major League Baseball Advanced Media's home office in New York City to be reviewed, and correct any errors. On August 20, MLB and the World Umpires Association, the umpires union, agreed to start reviews based only on whether or not a ball that is ruled a home run was fair or foul, or whether or not balls that clear walls are home runs according to each team's ground rules. This practice started August 28.