Although it hasn’t been exactly a hit, Sprint and Motorola’s Photon 4G has been rumored for a while to get a successor this summer. We first heard about the so-called Photon Q 4G LTE back in April, while just a few weeks back, we picked up on what looked like the first photo appearance of the new phone.

The plot now thickens even more, after spotting a mysterious Motorola XT897 gaining approval from FCC. While we can’t know for sure if the XT897 is the same device as the rumored Photon Q LTE, there are a couple of hints just about confirming it.

First off, this XT897 is sporting an LTE radio supporting 1900 MHz bands, according to FCC certification documents, which means that it can only be heading to Sprint. That being said, it’s pretty hard to believe that the nation’s third largest carrier will be releasing two different LTE-enabled high-end phones from Motorola in the space of a couple of months.

Furthermore, if we take a look at the XT897’s dimensions in the FCC internal documents, we’ll notice that they pretty much fit those of the original Photon 4G phone. Once again, this is not 100% conclusive proof that we’re dealing with the Photon Q, but it’s safe to assume that Sprint won’t come with two phones so similar to one another.

Other than the LTE support and dimensions, the FCC certification doesn’t allow us to find out very much about the future XT897. Then again, if this actually proves to be the Photon Q 4G LTE, we’re pretty sure, based on early rumors and leaks, that it will come with a 4.3-inch 720p HD display, Android 4.0 ICS out of the box, as well as a dual-core Snapdragon S4 processor and an included kickstand.

There’ll also be a slide-out QWERTY keyboard (hence the “Q” in the phone’s name), while all the other specs and features, but also pricing and availability details are still completely unknown. We’re guessing, however, that the handheld will be released by the end of the summer, so keep in touch with our website over the next few weeks to find out all the official details about the upcoming Photon Q.