The clues are piling up that the Oculus Rift virtual reality headset will not launch in retail by the end of the year.

Speaking on Facebook's most recent quarterly earning call, the company's chief financial officer David Wehner said that it has not announced any specific plans for shipment volumes in 2015 related to Oculus. "Oculus is very much in the development stage, so it's very early to be talking about large shipment volumes," Wehner said.

Oculus founder and inventor of the Oculus Rift virtual reality headset Palmer Luckey previously said that something would have to go "horribly wrong" to prevent the device from an official launch in 2015.

However, Luckey changed his position on the matter while speaking at an SXSW 2015 panel.

"I did say that before we made a lot of changes to our roadmap and we've expanded a lot of the ambition we had around the product and what we wanted to do," Luckey said. "Us partnering with Facebook allowed us a lot of things that we wouldn't have been able to do otherwise, like hire 300 people to be working on getting the Rift out as quickly as possible at the level we want it. I can't comment on the date one way or another in either direction but I can say that nothing is going horribly wrong. Everything is going horribly right."

Oculus could still surprise us and announce a release date for 2015, but given these two statements, that seems less likely.

Other competitors in the VR space have more firm plans. Valve and HTC's VR headset, Vive, is set to launch this year, Sony's Project Morpheus is set to launch in the first half of next year, and you can already buy the Innovator Edition of Samsung's Gear VR (made in partnership with Oculus) at Best Buy.