The head of Sprint (NYSE: S) Nextel’s CDMA business, John Garcia, is leaving, WSJ reports. No reason was given for his departure and a company spokesperson declined to comment. Sprint’s CDMA business makes up 70 percent of its customer base. Keith Cowan, president of strategy and corporate development, has been tapped as an interim replacement while the company searches for a successor. The move seems rather abrupt, particularly considering the carrier didn’t even take the time or effort to spin reasons for Garcia’s departure. Nonetheless, it follows a period of high executive turnover at the struggling carrier and indicates more problems might be afoot. CEO Dan Hesse has brought a new CFO on board, and within a year of being hired, ousted heads of marketing and sales and distribution. Prior to running the CDMA division, Garcia was SVP of product development and headed up Pivot, Sprint’s failed joint venture with several major cable operators. Release.

Update: We got our hands on Sprint’s announcement, but it’s still vague on the reasons for Garcia’s departure. The carrier also announced that Bill Morgan, SVP of brand management, will begin reporting directly to Hesse.