To replace Dooley, Viacom's board is said to be focusing on hiring from within. That seems to signal that controlling shareholders Shari and Sumner Redstone are increasingly focused on reuniting Viacom with its former corporate sibling CBS Corp. Dooley's successor would most likely be a placeholder until the Redstones can craft a merger that is palatable to the board of CBS Corp. and its chairman/CEO, Leslie Moonves. His happiness is essential, given that CBS is seen as one of the best-run television companies in the business.