According to ESPN's Marc Stein, the Mavericks have decided to hire former Pacers' coach Jim O'Brien.
Story going online at
— Marc Stein (@ESPNSteinLine) August 20, 2012@espndallas: Mavs have struck deal to hire ex-Pacers coach Jim O'Brien as Rick Carlisle's top assistant
More as the story develops...
**UPDATE**
Here's the story from ESPN Dallas.
Sources said that O'Brien received a multi-year deal, with Carlisle about to enter the first season of a new four-year extension.
O'Brien was fired by the Pacers halfway through the 2010-11 campaign after three non-playoff seasons in Indy. He previously coached the Boston Celtics (reaching the Eastern Conference finals in 2002) and the Philadelphia 76ers (for one season in 2004-05).