FILE - In this April 4, 2015, file photo, the roof of Minute Maid ballpark is wide open for an exhibition baseball game between the Houston Astros and the Kansas City Royals, in Houston. Over two-thirds of all major league teams now play in facilities that opened in 1992 or later, part of a ballpark boom that has changed how fans and players experience the game _ and has led to some contentious debate over how to pay for it all. (AP Photo/Pat Sullivan, File)