I've previously written about the possibility of Tony Stark / Iron Man heading into space to join the Guardians of the Galaxy (which is actually canon - the more you know!). But Iron Man isn't the only Avenger who could end up heading to outer space...
I'm of the (somewhat unpopular) opinion that, whilst I think Mark Ruffalo is a great Bruce Banner, the Hulk itself was not really adapted very well. (And it's not just cause of that dumb "I'm always angry" line.) But his Marvel Cinematic Universe storyline actually follows pretty closely with the founding of the Avengers.
In the comics Hulk (not Bruce Banner - there's a difference) is a founding member, but he leaves shortly after the founding (really shortly, like issue #2) because he realises that the other Avengers don't trust him.
Hulk to join the Guardians?
A while back there was rumours circulating that we were going to see Hulk making an appearance in Guardians of the Galaxy 2, which would actually be pretty neat. However James Gunn shot this theory out of the water...
"There was never a plan for the Hulk to team up with the Guardians of the Galaxy – I wouldn't want the Hulk to team up with the Guardians of the Galaxy! And it's all a bunch of complete bullshit."
Gunn has previously expressed that his Guardians films aren't bound by constrictions such as the Avengers storyline, and that he doesn't necessarily think that they're heading towards Infinity War. Thanos might have something to say about that, but fair enough.
Ruffalo has other ideas
However Mark Ruffalo has expressed an interest in Hulk in Space, and with four films left on his contract it looks like Infinity War would be the most likely platform for this to happen. Though there's currently no plans for a solo Hulk movie (due to yet another rights palava with Universal) elements of the Planet Hulk story could play a part in Infinity War, if we cross our fingers and wish really hard.
At the conclusion of [The Avengers: Age Of Ultron](tag:293035) Hulk's fate seemed uncertain. Leaving Banner's new love interest, Natasha Romanoff, behind, Hulk (again, not Banner) headed off in the Quinjet, crashing it near Fiji and... that's the last we've heard from him. It seems like a return to the dynamic we found him in at the beginning of The Avengers, but this time he's realised that there's nowhere on Earth that he doesn't pose a threat.
This could very well lead to a Planet Hulk-like storyline. But what is Planet Hulk and why is everyone so concerned with it?
Well, it's a pretty awesome and really very dark storyline from The Incredible Hulk comics. It all begins when the Illuminati (a superhero group which includes Iron Man) decide that Hulk is too damn dangerous to stay on Earth, so they shoot him out of the solar system. Dick move guys.
Instead of landing on a peaceful planet as per their intention, Hulk ends up on Sakaar where he is forced into slavery, fighting as a gladiator for the amusement of the Red King.
Long story short, he manages to free himself (with some help from the Silver Surfer), defeats the Red King, becomes the new King and marries Caiera (the Red King's former lieutenant who joins him on his quest). Unfortunately the shuttle in which Hulk crashed in eventually explodes, destroying the city and killing Caiera (who was pregnant with Hulk's child).
Enraged with grief, Hulk blames the Avengers who built the shuttle and leaves Sakaar with his warriors to take revenge on them on Earth, leading to World War Hulk.
So how could this tie in with Infinity War?
All we know at the moment is that there's no plans for Hulk between now and Infinity War, or if there is Joss Whedon is keeping them firmly under his hat.
However it wouldn't be a huge stretch of the imagination for Hulk to take off into space, just this time it would be a self imposed exile, rather than an Illuminati-imposed one, and therefore not one which would led to Hulk attempting to decimate the planet (which is something I think we can all agree we can do without).
What we really need is a solo Hulk outing so that we can get some good old fashioned gosh-darn character building up in this house; however since that's not going to happen (looking at you Universal), taking elements from the Planet Hulk story such as the exile could go a long way towards building some meaningful story for the Hulk.
It also gives Hulk an excuse to be in space right around Thanos-punching time when Infinity War rolls round, and honestly who doesn't want to see that?