On July 15, 2001 Umpires file a grievance against Major League Baseball, saying the commissioner’s office is pressuring them to call more strikes by keeping track of total pitch counts. As part of these efforts, cameras were installed over the weekend, July 13th and 14th, at Shea Stadium to track each pitch. Fenway Park and Shea are the only parks with the tracking system, which is similar to that used on FOX’s broadcasts, but major league officials hope to have four more by September.
Source
Baseball Reference July 15