Walking Dead showrunner Scott Gimple is teasing that we might get to see the Whisperers on the show a bit earlier than expected.

In a chat with Comicbook.com, Walking Dead showrunner Scott Gimple dropped a big hint that we might see one of the comic's most infamous factions earlier than expected. While the TV series has only just begun to explore Negan and the Saviors, Gimple teased that fans might not have to wait too long to meet the next group of bad guys on the show. Comic book fans, Gimple is indeed talking about the Whisperers.
It's been long rumored that the Whisperers might show up in season 7, especially after the official Walking Dead Instagram account shared a picture that seemed to tease as much:

If that picture doesn't quite click with you, here's some context: the Whisperers are known for displaying severed walker heads on sticks in the comics. Of course, that's far from a confirmation.
The rumors started up again after the synopsis for next Sunday's episode, "Swear," dropped on the internet: "Someone stumbles upon a brand new society, and this society is unlike anything seen before."
The group Tara and Heath are about to encounter could very well be the Whisperers from the comics. Of course, when asked about it, Gimple was very hesitant to confirm as much, even if he did hint the Whisperers could appear at an unexpected time:
If we've gotten this far without saying anything about them, I'd like the audience to discover this group when it's on screen. I will say ... I mean, it's not the Whisperers. I will also say, though, that it's not impossible that the Whisperers could come along or aspects of them could come along earlier than the timeline of the book, but certainly not this early.
It sounds like Gimple is saying that, while the show won't come out and officially introduce the Whisperers on Sunday, we could very well get a hint of their arrival in the episode. Perhaps a flesh-wearing creep in the woods? Either way, we'll find out this Sunday.