First off, seeing Nathan Fillion on a spaceship warms my heart. Second—why is he dressed like a Space Barbarian on the set of Guardians of the Galaxy Vol. 2? Fillion posted this mysterious image on his Instagram noting that it’s “from a scene you won’t see” in the film. This led many to speculate that he had a cameo and it was cut. However, James Gunn chimed in to clear things up…sort of.
— James Gunn (@JamesGunn) April 21, 2017
Note that Gunn didn’t say that Fillion wouldn’t be in the film at all, only that this picture isn’t from a scene. So there still might be a chance that Fillion the Space Barbarian makes an appearance in GOTG Vol. 2 or one of it’s ridiculous FIVE post-credits scenes. We shall know soon enough.