The sudden announcement earlier this week that former Microsoft CEO Steve Ballmer was stepping away from the Microsoft board of directors raised a number of questions. But the elephant in the room, so to speak, is another former Microsoft leader who's been hanging around the firm's Redmond campus a lot more than usual lately. Is it finally time for Microsoft co-founder and tech industry icon Bill Gates to step away from the software giant for good as well?

This kind of question raises alarms in certain quarters. But I can think of a number of reasons why Gates is no longer needed at Microsoft and is indeed just a hindrance to the firm moving forward. Furthermore, my suspicion is that his more active involvement this year is mostly a ruse to help smooth the transition to the Satya Nadella era. I think Microsoft is plotting Gates' exit strategy.

Left unsaid in Ballmer's departure was the weirdness of him sticking around after having been almost certainly asked to step down as CEO last year. Microsoft handled Ballmer's exit as well as it could, but it's pretty clear that he missed the boat on the biggest computing trend of the past decade, leaving the company as an also-ran in mobile, a market dominated by Google and Apple. In almost any other company, that CEO would have been shown the door. But when Satya Nadella was selected as the next CEO, Mr. Ballmer simply moved to the board, where he sat alongside Nadella at meetings.

This was likely awkward for everyone, but more important, it's also unsettling to investors. The board is charged with helping set Microsoft's strategic direction. It doesn't seem like a former CEO should be part of that decision making, does it?

Taking the role of an armchair quarterback, it's apparent that Ballmer's exit from the board was in fact inevitable and that it was just a matter of timing. It's possible that Microsoft allowed him to position that exit as he wished, much as he was allowed to do so when he stepped down as CEO. And Ballmer buying the LA Clippers basketball team was an obvious excuse to make this transition.

I do really feel that these events are all about managing transitions, in fact. Ballmer stepped down as CEO but stuck around for a while, as did Bill Gates years earlier. Gates slowly drifted away from Microsoft, after struggling with his reduced role for a while, which makes sense when you consider that he was both the face and mind of Microsoft for decades. But he did step aside, and indeed he left the day to day business of Microsoft years ago to focus on his health and education work at the Bill & Melinda Gates Foundation.

And then Ballmer happened. With Mr. Nadella's ascension to CEO, Gates actually came back to Microsoft, and in addition to his ongoing role as a board member, he is now special advisor to Satya Nadella on key development projects, and allegedly spends one-third of his time working at Microsoft again.

If you're going to criticize Ballmer for missing key tech trends, it's equally fair to criticize Gates for putting Microsoft in such a position to begin with. A brash upstart in the early days of the PC industry, Gates still ran Microsoft like a startup in the late 1990s and ran afoul of antitrust regulators in the US, Europe, South Korea, and elsewhere. Worse, Gates belligerently defied these regulators, leading the company into a decade of oversight and top-heavy decision making that made it impossible for the gigantic company to act quickly. Ballmer missed mobile, yes. But he was set up by Gates.

And now Gates is back at Microsoft, like Michael Jordan returning the NBA's Washington Wizards for a few unspectacular years well past his prime. Why?

Clearly, this was mostly about managing the transition. About soothing worries, internally and externally, about handing the company over to a relative newcomer, someone who hadn't been there since the beginning. (But then, neither had Ballmer, though most people think he was one of the original employees: Mr. Ballmer joined Microsoft in 1980, a full five years after it was founded.)

Ballmer's recent exit from the board of directors suggests that this transition has been embraced internally, and Microsoft is signaling to investors that it is moving forward. A Gates exit would probably be perceived more negatively, even though his real impact on the company recently is probably minimal at best. But I think it's another important step in this transition, arguably the final important step. Satya Nadella will always be somewhat constrained by the past—and old thinking—while Gates is there. We can't have a new Microsoft, not really, until he's gone.

Look, Bill Gates' legacy is assured. He is almost personally responsible for spreading personal computing to the masses, and his aggressive business practices allowed Microsoft to establish several long-lasting product lines that could sustain it for years and years to come. But when I look at Microsoft today, I see one piece that doesn't fit, one square peg that's been forced into a round hole. And that's Bill Gates.