Bethesda's schedule between now and year's end looks tight, however it seems the developer has another unnamed project in the works that's due in 2017.
As reported by VG24/7, Tek Syndicate's recent interview with Pete Hines sees the Bethesda exec rhyming off all of the games it already has in the pipeline—the majority of which were shown at its E3 showcase.
"...We've got Skyrim Switch, we've got Wolfenstein 2 and The Evil Within 2, and Quake Champions free-to-play, and Elder Scrolls Legends free-to-play, and Elder Scrolls Online and Dishonored Death of the Outsider—we have a tonne of stuff going on," Hines explains.
That part we already knew. The following, however, we didn't. Hines adds: "We even have a game coming out this year that we haven't even told anyone about yet. They can wait, it won't be so long."
Skip to 2.40 below for that.
As you can see, when pressed by Tek Syndicate about the specifics, Hines remains tight lipped. When asked directly if the mysterious project is "a new IP", Hines replies: "I'm not telling you. It's a good try, I'm just not telling you."
As VG24/7 rightly suggests, the chances of this unnamed venture being something big is very unlikely but, with less than four months left on the calendar, I guess we'll find out soon enough.
Update: Despite the pretty explicit statement above, Hines has since tweeted this to the contrary.