Frustrated with the lack of character development for Dr. Crusher, Gates McFadden clashed with producers which led to her release after the first season. In Season 2, Dr. Crusher was replaced by Dr. Kate Pulaski, played by Diana Muldaur. However, producer Rick Berman personally phoned McFadden to convince her to return for Season 3.
Star Trek: Phase II was an unproduced television series created by Gene Roddenberry as a sequel to Star Trek: The Original Series. It would have featured most of the original crew, minus Spock who would have been replaced with a full vulcan named Xon. However, Barry Diller, Chief Executive Officer of Paramount Pictures, decided the pilot, "In Thy Image", would work better as a feature film, and the series was eventually converted into Star Trek: The Motion Picture.