In the absence of other clues, fans are focusing on the one detail in the trailer that might possibly be used as an identifying feature: the white hat. In the comments of the teaser’s post on Instagram, speculation was rife as to whom the hat might belong to. Some think it looks like a hat worn by Walker (Ryan Bingham), the former prisoner who Rip (Cole Hauser) brings onto Yellowstone Ranch, but who never seems to take to ranch life — though others point out that the shape of the crown doesn’t match up.
A few more fans suggest that characters such as Colby (Denim Richards) and Teeter (Jennifer Landon) have been seen in white hats before, though given what those two went through for the sake of the ranch in the latter parts of Season 3, it’s tough to see them coming back and betraying the Dutton family so soon.
One fan pointed out that there’s one antagonist with a good reason to be standing in the river: Roarke (Josh Holloway), who counts fly fishing among his hobbies. But Roarke seems to favor baseball caps over cowboy hats when he needs some headgear, so unless he adopted the latter as some kind of symbolic taking-over-the-crown type of gesture, it would be a little out of character for him.