Usually, when a company reaches the day before it's supposed to officially release a new gadget, you can be relatively sure that there won't be any more unexpected delays announced in the intervening 24 hours. We have to say "usually" because of Nvidia's surprise announcement today that tomorrow's planned launch of the Shield handheld game console has now been pushed back to "next month."

In a post on the official Nvidia blog, the company writes that "final quality-assurance testing has just turned up a mechanical issue that we’re not happy with." The issue can apparently be traced back to "a third-party mechanical component" that is now being worked on by the supplier. "We apologize to those who have preordered Shields and to all those who are waiting for them to go on sale. But we want every Shield to be just right."

The Shield's rollout has had a rather compressed schedule as far as game consoles go. The Tegra 4-powered portable—Nvidia's first dedicated game console—was first revealed less than six months ago at a CES event. Nvidia opened pre-orders for the device just last month, ahead of an announced June launch window. Then Nvidia took the surprise step of lowering the launch price of the system from $349 to $299 just last week, a move that could indicate lower-than-expected consumer interest at the original price.

While the Shield is primarily focused on running Android Jelly Bean games and apps with its built-in analog sticks and buttons, Nvidia is also heavily selling the ability to stream Steam games running on a nearby PC over a local wireless network. That feature has been surprisingly functional and lag-free in convention demonstrations, but we're still eagerly awaiting actual production units for in-home tests.