Complex sentence: In an interview, William Fichtner stated that he would be returning as Eric Sacks; however, for unknown reasons, he was not in a trailer for the film or a TV spot, and ultimately did not appear in the final film.
Split into simpler sentences: In an interview, William Fichtner stated that he would be returning as Eric Sacks. However, for unknown reasons, he was not in a trailer for the film or a TV spot, and ultimately did not appear in the final film.