Here's why this rumor makes sense from the Microsoft perspective.
Microsoft is hot to acquire non-U.S.-based companies so as to spend some of its overseas cash. Mojang AB is based in Stockholm, Sweden. Nokia's devices and services business, which Microsoft bought a year ago for $7.2 billion, was its last big overseas purchase.
Though some on Wall Street have been pressuring Microsoft to sell off Xbox, Nadella said: "Microsoft will continue to vigorously innovate and delight gamers with Xbox."
"We also benefit from many technologies flowing from our gaming efforts into our productivity efforts — core graphics and NUI in Windows, speech recognition in Skype, camera technology in Kinect for Windows, Azure cloud enhancements for GPU simulation and many more," Nadella said in that memo.
"Bottom line, we will continue to innovate and grow our fan base with Xbox while also creating additive business value for Microsoft."
Microsoft has been an advocate of using games and gamification to get all types of users interested in its products and technologies.
All that said, Markus Persson, the founder of Mojang, has been opposed to outside investment and isn't much of a fan of big companies, including Microsoft, as the Journal noted.