Today a listing for The Legend of Zelda: Skyward Sword has been posted by Amazon.
The listing is bare-bones with no images or description. Amazon UK has listed games prior to their announcement before in the past. So it is possible that this means an announcement will be coming from Nintendo soon in the future. There have been rumors of a Nintendo direct coming this month, this. It has also been speculated that a Super Mario 35th Anniversary collection is coming. This would bring a strong line-up of titles to round out the end-of-year release schedule for Nintendo. With the recent announcement of a Switch port of Pikmin 3 for October Nintendo is already starting to announce the titles that will be coming this holiday season, so we should find out soon if this listing is simply an error or not.