Avengers 4 Theory: 10 Clues Bucky Will Take Over As Captain America

10. Sebastian Stan's Contract

When it comes to predicting the layout of the MCU's future, contracts prove to be a vital tool. This isn't to say that they can predict the beats of the films down to a T (Robert Downey Jr.'s is extended on a film by film basis), but they can give us an idea of how integral characters are in the MCU writer's room.

When he signed on for Captain America: The First Avenger, Sebastian Stan also signed a nine (yes, nine) picture deal with Marvel Studios. Avengers 4 will mark his fourth appearance in the franchise should he genuinely return, and, though it could be argued that contracts 'spoil' what's to come, we know not yet what form those remaining five films will take - if they even do at all.

What is clear is that Marvel were planning for the future when Stan signed on, and that agreeing to a nine picture deal is a huge investment.

Bucky Barnes has already proven to be an integral aspect of the franchise as well, and with the character having adopted increasing prominence in each successive appearance, Avengers 4 could be the perfect place to make the next jump in the character's overarching journey.