Microsoft this week announced that Xbox Chief Product Officer Marc Whitten, a 17-year veteran of the firm, would be leaving to become Chief Product Officer of Sonos, a living room entertainment firm. The departure was unexpected, and it comes in the wake of a botched Xbox One launch that also saw the departure of another key executive, Don Mattrick.

"I have had the extreme pleasure over the last 14 years to work on the greatest product with the greatest team and for the greatest community," Mr. Whitten wrote in a prepared statement. "Xbox is so special because of the amazing team I've had the opportunity to work with and because our fans are the most incredible fans on the planet. It has been the highlight of my career to work on a product so loved. It's incredibly tough to leave, but I am confident the best days are ahead for Xbox fans, in the capable hands of a very talented team."

It's unclear what really drove Whitten's departure, but a few obvious theories emerge.

With Xbox One falling further behind the Sony PlayStation 4 each month, Microsoft's senior leadership might have been looking for more change from its flailing Xbox group, which will now report directly to Terry Myerson, who heads up the firm's recently unified client OS development. He will work with Xbox Corporate VP of Strategy and Marketing Yusuf Mehdi and Microsoft Studios lead Phil Spencer to "find a great replacement" for Whitten.

And of course, the company is still undergoing the "One Microsoft" reorganization that has seemingly accelerated now that Satya Nadella has taken over as CEO. It's possible that this is part of a wider culling of executives that started almost immediately after his promotion. And future executive departures tied to this change are likely.

Whatever the reason, Mr. Whitten helped "deliver three console generations," including Xbox (2001), Xbox 360 (2005), and now Xbox One (2013), as well as the Xbox Live online services. But while Microsoft sold 25 million original Xbox consoles and then 80 million Xbox 360s, the bad news started to outweigh the good. Endemic Xbox 360 reliability issues caused that console to become the most expensive warranty repair in consumer electronics history, with a bill estimated at over $1.1 billion. And the Xbox One, as noted, has gotten off to a bad start because of its high price, ham-handed messaging, and inept marketing. (Microsoft refers to this publicly as "the most successful launch in Xbox history.")

In the wake of the 2013 E3 trade show, where Microsoft and Sony both officially launched their next-generation consoles, Don Mattrick, the president of Microsoft's Interactive Entertainment Business, and the face of Xbox at the time, abruptly left the company. He was held responsible for botching the Xbox One launch while Sony capitalized on Microsoft's mistakes. And it was pretty clear Mattrick wasn't going to get a featured leadership position in Microsoft's then-pending reorganization, a fact that might have help jumpstart his exit.

To be fair, Mr. Whitten isn't the only high-profile video game executive to jump ship in recent weeks. Sony Computer Entertainment America (SCEA) president and CEO Jack Tretton unexpectedly announced his departure from that firm earlier this month as well.