According to TVLine (who first reported the recasting news), Paulson's AHS: Freak Show shooting schedule conflicted with returning to Grey's Anatomy, so she was unable to reprise her role. That's when Pressman boarded the show to take over for Paulson, having already guest-starred on Shonda Rhimes' second hit show Scandal as the sister-daughter (it's a thing) of Lisa Kudrow's character. She will appear on two episodes of Grey's this fall, with young Richard Webber still being played by J. August Richards. 

But that's not all! Kate Burton, who played present day Ellis Grey in previous seasons of Grey's before her character died, was supposed to appear in the season 11 premiere in flashbacks, but her scenes have been cut from the episode. She is still slated to appear later this season, though.

Why are both of these casting shake-ups a big deal when the character of Ellis Grey is deceased? As revealed in the season 10 finale, Ellis and the former Chief of Surgery Richard Webber (James Pickens, Jr.) had an affair many years ago that resulted in a daughter that Ellis gave up for adoption. That child, Maggie (Kelly McCreary), just landed a job at Grey Sloan Memorial Hospital, surprising Richard (who clearly didn't know about her), and is bound to piss her half-sister Meredith off. The premiere will show, in flashbacks, the story of Ellis and Richard.

 Add a newly-discovered daughter and half-sister to the long list of reasons why working at Grey Sloan Memorial Hospital is bad for your health.

Grey's Anatomy returns tonight at 8 p.m. on ABC.