Ellerbe Becket, Kansas City, Mo., has replaced Gehry Partners as architect for basketball’s Barclays Arena at the beleaguered Atlantic Yards mixed-use development in Brooklyn, N.Y. The original project’s two main consultants, New York City-based structural engineer Thornton-Tomasetti and mechanical-electrical-plumbing engineer, WSP Flack + Kurtz, will remain. Developer Forest City Ratner Cos. says it hopes to unveil new images of the arena late this month. Ratner intends to break ground later this year in anticipation of a completed arena for the 2011-2012 National Basketball Association season. Bruce Ratner owns the New Jersey Nets and plans to move the team to Brooklyn.