Populous, formerly known as HOK Sport, has been a popular firm for teams designing new stadiums. The firm has designed 19 major league ballparks, including some of baseball's most noteworthy. Among those it has designed are PNC Park, Camden Yards, new Yankee Stadium, Marlins Park, AT&T Stadium and Target Field. A full list of ballparks Populous has designed can be found on its website. It was also in charge of improvements to Wrigley Field.
In fact, of 14 ballparks opened since 2000, Populous has designed 13 of them. The Milwaukee Brewers' Miller Park is the lone exception, having been designed by NBBJ and HKS, Inc.
Populous has also done architectural design work for the stadiums featured in the upcoming XXII Winter Olympics in Sochi, the 2012 Summer Olympics in London, Wembley Stadium, Emirates Stadium, Heinz Field, Sun Life Stadium, Gillette Stadium and Reliant Stadium, along with many, many others.
The Braves recently closed a deal to purchase the land in Cobb County that will soon house the new ballpark, paying $34.2 million for 57.1 acres. The team is hoping to move to the new stadium by Opening Day of 2017, at which time Turner Field will be demolished.