An unknown Samsung device with model number SPH-L520 has been found visiting the FCC looking for approval on its communication radios. Its dimensions are largely similar to the Galaxy S4 mini, and it supports Sprint's native LTE frequencies, so we could looking at a variant of the device for carrier.
There's no confirmation on whether this really is the S4 mini though, so don't be surprised if it turns out to be just another device that looks like the S4 mini. We'll keep an eye out for more information and send you guys a hoot about anything we find.