prior to the 2017 mlb season, the rules were amended to allow a manager to order an automatic intentional walk. mlb and the mlb players association (mlbpa) discussed the possibility of introducing the pitch clock at the major league level for the 2018 season. mlb opted against imposing it unilaterally, over the opposition of the mlbpa. before the 2018 season, milb took major actions, including adding pitch clocks at all levels, beginning each extra inning with a runner on second base, and restricting the number of mound visits for full-season class a through triple-a teams. also, the arizona diamondbacks of mlb announced they would introduce their first bullpen car in 2018.