Chase Field, formerly Bank One Ballpark, is a retractable-roof stadium in Downtown Phoenix, Arizona. It is the ballpark of Major League Baseball's Arizona Diamondbacks. It opened in 1998, the year the Diamondbacks debuted as an expansion team. Chase Field was the first stadium built in the United States with a retractable roof over a natural grass playing …Chase Field, formerly Bank One Ballpark, is a retractable-roof stadium in Downtown Phoenix, Arizona. It is the ballpark of Major League Baseball's Arizona Diamondbacks. It opened in 1998, the year the Diamondbacks debuted as an expansion team. Chase Field was the first stadium built in the United States with a retractable roof over a natural grass playing surface, although it has used artificial turf since 2019.