UPDATE: Here is the story from Jordan Bastian at Indians.com.
Niebla is officially the interim pitching coach, though I would not be surprised if he takes over the position permanently at some point. Niebla has worked his way up through the Indians farm system, with stops in low-A Columbus in 2001, high-A Kinston in 2002, rookie league Burlington from 2003-2005, Lake County from 2006-2008, Akron in 2009, and Columbus since. In that time he has worked with a lot of the significant pitchers in the Indians system over the past decade.
In 2011 Niebla took the youngest pitching staff in the International League, playing in Columbus' small stadium, to a 3.94 ERA. In 2009, he led the Aeros to the lowest ERA of the Eastern League. In 2008, the Lake County staff was the youngest in the Sally League and had the third lowest ERA, 3.44. In other words, he has been effective working with Cleveland's young pitchers in the recent past.