Tony Daniel, the artist who was teamed with Andy Diggle on Action Comics, and who was announced by DC as taking over the writing chores on the book with Diggle’s departure (see "It's One and Done Andy Diggle on 'Action Comics'"), is leaving Action effective with issue #21 in June. After finishing his efforts on Action Comics #21 Daniel will turn his efforts to an as-yet-unnamed massive DC project.
Writing on his Facebook page, Daniel gives his reaction to Diggle’s departure: "I can only say I feel bad that he made that decision. I think it was the wrong one, but it was his to make. For the remainder of the arc I will be working off of his plots to finish off the first arc. So essentially I have become the ‘scripter’ in the credits with Andy as the ‘plotter.’ As for myself, I end my short run after I complete the first arc, which ends with issue #21. This was preplanned since last fall as there is another project that I’ll be taking on, and assisting with, a massive project with DC."
This now leaves the matter of who will take over Action Comics after issue #21. So far DC has not announced a creative team for the title, but given the debut of the Man of Steel movie in June, it would appear to be imperative for DC to come up with creators who can build on the momentum created by Grant Morrison, who used his "New 52" stint on Action Comics to reboot the series as the adventures of a younger Superman, as well as on whatever push for the character created by the big-budget Superman movie.