At a red carpet event for his new Hulu series "Pam & Tommy," Stan said that the new Captain America himself, Anthony Mackie, could keep him out of "Captain America 4" should he end up having any say in the matter. 

"I don't know. I really don't know. I really hope Anthony Mackie doesn't have any say in it ... because if he has any say in it, I'm not in 'Captain America 4,'" Stan said about his potential involvement to Extra

Stan followed up by making it clear he was kidding about his co-star, calling Mackie "the best." The two actors have frequently ribbed each other over the years, in a dynamic very similar to their characters in the MCU. Stan and Mackie co-led "The Falcon and the Winter Soldier" series, which was an essential extension of Captain America's story as it dove into the aftermath of "Avengers: Endgame" and answered all questions about who the next shield-carrier would be. With that in mind, it may be difficult to make a "Captain America 4" without at least acknowledging Stan's Winter Soldier in some way, so a return (if not a full-on supporting role) seems very likely.

Producer Nate Moore previously teased the film will act as a direct sequel to "Falcon and the Winter Soldier" with Sam Wilson's Captain America being something of an "underdog," compared to his super-powered predecessor. "He's not a super soldier. He's not a hundred years old. He doesn't have the Avengers. What happens with this guy who announces publicly kind of, without the support, 'I'm new Captain America.' What happens next?" the producer said (via Phase Zero Podcast).