Ever since Mark Ruffalo took over the role of Bruce Banner in the Marvel Cinematic Universe, the character's angry alter ego known as the Hulk has been reserved for supporting parts in The Avengers films. Ruffalo signed with the studio for six pictures but said before Avengers: Age of Ultron released in theaters this summer that his involvement with the studio could go on for longer.
It's a given that the character will be back for one or both parts of Avengers: Infinity War in 2018-19, but will the Hulk really be absent from the rest of Phase 3? Unlikely.
Given the amount of characters, story arcs, and set pieces that need to be squeezed into directors Anthony and Joe Russo's Infinity War, it'd be a waste of time finding out where Hulk's been for the last few years since running off at the end of Age of Ultron (and re-recruiting him into the team to prove he's still a hero). So which other Phase III film(s) could Bruce Banner and his green alter-ego appear in?
Banner was initially set to return in Captain America: Civil War, and Ruffalo was spotted with the cast during the final stretch of shooting on location in Germany, but the part was cut so Marvel could bring him back later instead. Unfortunately for Hulk fans, there seems to be little interest in giving Banner another solo movie or attempting to adapt Planet Hulk/World War Hulk stories from Marvel Comics anytime soon - so his return will rely on another character's story.
Guardians of the Galaxy writer and director James Gunn has stated repeatedly that the Hulk will not be in Guardians of the Galaxy Vol. 2, so where else could Ruffalo return in Phase 3? According to JoBlo.com's scoop, it may be in Thor: Ragnarok.
This one comes as an unexpected possibility, given the setting of the Nine Realms for the third Thor movie (which will cover the "end of all things" as its name implies). That being said, the superhero movie genre strategy in Hollywood is leaning towards "event" style team-ups and crossovers after new characters are introduced - and this would be a neat way to bolster the marketability of Thor: Ragnarok. After all, the Ant-Man sequel is going to be co-headlined by Wasp and we all know Captain America: Civil War is serving as the big intro to Black Panther and Spider-Man.
JoBlo's sources also reveal that Thor 3 will feature what they quote as a "distant planet” that is "not Asgard and not Earth." Before you go thinking Planet Hulk, such a story doesn't fit within Ragnarok - so perhaps this new location is simply the realm of Muspelheim, home of Surtur and the Fire Demons who are integral to the story of Ragnarok. Unless, of course, it's Loki who snagged Hulk from Earth to pit him into an arena battle for his entertainment?
Looking back on previous Marvel exclusives from JoBlo's insiders, they were spot on with regards to leaking details on Ant-Man and Civil War that were later confirmed, just as they were in picking out Ronan the Accuser as the villain of Guardians of the Galaxy. Then again, they were off in reporting Ant-Man as the start of Phase 3 and Guardians of the Galaxy 2 coming out as the first movie of 2016, so it's a wait and see. It does seem likely Hulk will show up somewhere before Infinity War though, otherwise he'd be the only Avenger who doesn't.
Captain America: Civil War will release on May 6, 2016, followed by Doctor Strange - November 4, 2016; Guardians of the Galaxy 2 - May 5, 2017; Spider-Man - July 28, 2017; Thor: Ragnarok - November 3, 2017; Black Panther - February 16, 2018; The Avengers: Infinity War Part 1 - May 4, 2018; Ant-Man and the Wasp - July 6, 2018; Captain Marvel - March 8, 2019; The Avengers: Infinity War Part 2 – May 3, 2019; Inhumans – July 12, 2019; and as-yet untitled Marvel movies on May 1, July 10 and November 6, 2020.