According to GFR, Chris Pratt is set to star in an adaptation of The Micronauts, a companion toy line to Hasbro’s Transformers. While his specific role is unclear at the moment, it would not be surprising if he was cast as the token human amongst otherworldly beings like Shia LaBeouf, Mark Wahlberg, Hailee Steinfeld, and Anthony Ramos before him.
And James Gunn is out. What were they planning to do, have him randomly show up in the next Avengers, possibly by himself? What would even be the point?
Seems like a good time for him to leave the franchise.