'Avengers: Endgame' directors and stars on why Sam, not Bucky, became the new Captain America

It was one of the biggest questions heading into Avengers: Endgame. With Chris Evans all but confirming on social media that the film would be his last go-round as Steve Rogers, fans debated which hero would pick up the shield of Captain America going forward in the Marvel Cinematic Universe.

In the comics, both his troubled ex-war buddy Bucky Barnes, a.k.a. the Winter Soldier (Sebastian Stan), and his winged partner in crimefighting Sam Wilson/Falcon (Anthony Mackie) served stints as the star-spangled hero, so the logical choice would be one of them. But who?

"We wanted to make sure that we gave it proper thought in terms of who would move forward," co-director Anthony Russo told Yahoo Entertainment at San Diego Comic-Con, where he and brother/co-director Joe Russo were promoting the home release of the top-grossing film of all time.

And so they ultimately settled on Sam over Bucky, whose dark path through the MCU included a turn as the assassin responsible for the deaths of Tony Stark's parents.

"It seemed really appropriate for the connection that Cap and Sam had,” Anthony said. “Ever since they met in [2014's Captain America: The Winter Soldier] there seemed a very common bond between the two characters in terms of their military background, their humility, their sort of commitment to serving. It just seemed like that would be the person Cap would entrust."

But they didn’t immediately dismiss Bucky for the job.

"We had the conversation, but … we try to logic it out and sit in the room and talk through what makes the most sense from an arc standpoint and from a logic standpoint, and Sam made the most sense,” Joe explained.

Was it ever even close?

Mackie, who has long bemoaned the fact that he doesn't get full scripts for Marvel films (because of his Mark Ruffalo-esque knack of dropping spoilers), didn't find out about his character's new designation until "a day or two" before they shot that pivotal climactic scene.

Evans showed him the script while they were watching football at the former’s place in Atlanta. "It was crazy, I was blown away," said Mackie.

And for both Mackie and Stan, the decision was no-brainer. Stan, in fact, doesn’t believe Bucky stood a chance.

"It makes no sense for [Bucky to be Captain America]. Why would you give it to the guy that's been trying to have a whole new history outside the thing that he's been trapped by?

Falcon, to Stan, made sense. "He's actually been [Steve’s] right-hand man for a long time at this point if you think about the movies and the time."

"And," Mackie added, "we're only one movie away from [Bucky] trying to kill everybody."

Steve Rogers may now be out of the picture, but The Sam and Bucky Show is just getting started. Literally. Mackie and Stan, who just hours after this interview playfully passed the shield back-and-forth at Marvel's headline-making Comic-Con panel, will debut on Disney Plus's The Falcon and Winter Soldier in Fall, 2020.

By Kevin Polowy, Yahoo Entertainment

Avengers: Endgame arrives on on Digital in HD and 4K Ultra HD™ on 19 August, followed by a physical release on 4K Ultra HD, Blu-ray™, 3D Blu-Ray™ (3 discs) and DVD on 2 September, 2019.

Watch directors Joe and Anthony Russo talk about nearly decapitating Captain America: