The rumor was based off an advertisement on WWE.com (seen here) that lists "The Show-Off" as one of many stars slated to appear. Keep in mind, next week’s episode is live from WWE's home turf of Hartford, CT, so it wouldn't seem too out of sorts to see one of the company's top stars returning that night.
Advertisements listing Dolph Ziggler's WWE return for next week are actually outdated. As of today, Ziggler is still not medically cleared to return from his concussion he suffered a few weeks ago. There is the possibility that Ziggler may return to cut a promo, but as far as in-ring competition is concerned, it's likely he's not returning yet.
Ultimately, I have to wonder what the company plans on doing if Ziggler is once again unfit to perform at another pay-per-view. Obviously, the powers that be could strip him of the title citing the 30-day mandatory title defense clause.
This move would allow the company to book a match for the newly vacated title at next month’s Payback pay-per-view. With a little over two weeks left before the event, this might not be a terrible move by the WWE. Don't get me wrong, Ziggler has done an outstanding job at getting to this point in his career. However, he needs to take this concussion seriously and utilize whatever time is given to him in order to properly heal.
Overall, I am not entirely against a move like this. The fact is, Ziggler is only 32 and still has plenty of time to get back to the top. That is especially true if the WWE decides to throw him back in the World title mix upon his return.
That being said, we will have to wait and see what the future holds for Ziggler over the next few weeks.