While the recent season three deaths of Matthew Crawley (Dan Stevens) and Sybil (Jessica Brown Findlay) seem to guarantee that neither will be returning for the series' fourth installment of Downton Abbey, the same can't be said for the Mrs. O'Brien (Siobhan Finneran) character, who recently left the show.

The reason that Finneran's fate isn't exactly set in stone is quite simply because Mrs. O'Brien isn't dead.

Carter Matt reported that O'Brien ended up going out in a certain way in which Downton executive producer Julian Fellowes hoped to see both Matthew and Sybil make their exit, which is with a door open for a series return. 

However, it's being said that there's a logical reason behind Finneran's departure in that she may have been found acting work elsewhere.

While conducting an interview with This Morning, Finneran spoke about the possibility of returning to the show in the future, amid comments that she wasn't interested in doing so.

"The door has been left open to return.  We don't know what happens to her ... She may well fly back on her broomstick at some point."

Although fans will undoubtedly miss the O'Brien character, it does provide a change in the cast, giving the show's writers additional possibilities and new dynamics to create for the current cast.

Other new characters reportedly joining the fold for Downton Abbey's fourth season include Dame Harriet Walters as an old friend to Dowager Countess (Maggie Smith), Dame Kiri Te Kanawa as a guest of the home, aristocrat Charles Blake (Julian Ovendon), Green (Nigel Harman), and the Duchess of Yeovil (Joanne David).

The series is set to make its return at some point in the fall of 2013.  Information on the upcoming season will be posted as it comes out.

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