The Chief Experience and Technical Officer for Microsoft's gaming division, J Allard, is rumoured to have quit the company.
The CTO has been consistently absent from public appearances made by Microsoft since the release of its Zune HD media player, adding weight to the rumours.
Allard's rumoured exit from the company is expected to be the result of his increasing disagreements with Microsoft CEO Steve Ballmer over the release of his project, the Courier tablet, which had been expected in early 2011.
Microsoft insiders claim that Allard left the company in order to pursue other projects, and that the scrapping of Courier has nothing to do with his exit.
During his time at Microsoft's gaming division, Allard has been credited with single-handedly turning around the fortunes of the company's Xbox games console in the face of stiff competition from rivals Sony and Nintendo. Allard was also responsible for organising all media and PR coverage surrounding the device.
Allard's departure has not been confirmed by Microsoft, and his company profile still appears on the Microsoft website.