Google is reportedly developing a standalone virtual reality headset that won't require a PC, console or mobile device to operate, according to sources "familiar with the matter" cited by the Wall Street Journal.

This is chiefly notable for how far-fetched it seems, given that we've yet to see a high-profile VR headset that's not a peripheral for an established platform. However, the Wall Street Journal does note that some sources have cautioned this project is "early in development" and may never see release.

The notion that Google is working on a standalone VR headset seems a bit more believable this year in light of the company's decision last month to name longtime employee Clay Bavor its inaugural vice president of virtual reality.

A few weeks ago Google announced it had shipped more than 5 million of its debut VR headsets, the smartphone-powered Google Cardboard (pictured), in just over a year and a half.

Company chief Sundar Pichai mentioned the figure in a conference call with investors on Monday, and according to CNet he noted that "it's still incredibly early innings for virtual reality as a platform...Cardboard is just a first step, but we are excited by the progress we have seen."