Grey’s Anatomy: Why Kate Walsh’s Addison Is Returning (& Why She Left)

Kate Walsh is returning as Dr. Addison Montgomery (formerly Montgomery-Shepherd) in Grey’s Anatomy season 18, but why did the character leave in the first place? Walsh made her debut in the show’s season 1 finale as a neonatal surgeon and Derek Shepherd’s wife. Created by Shonda Rhimes, Grey’s Anatomy debuted on ABC and is one of the longest-running medical drama’s in television history. Due to Walsh’s popularity, the star went on to play the lead character in Grey’s Anatomy’s first spin-off, Private Practice.

Walsh will reprise her role as Addison Montgomery in a multiple-episode arc. However, her storyline has yet to be revealed. Walsh left Grey’s Anatomy in season 3 for her own medical drama, Private Practice. There Addison continued to work as a neonatal surgeon and welcomed the drama moving to Los Angeles brought. This included a close-knit friendship with Amelia Shepherd (Caterina Scorsone), Derek’s sister, who started off on the spin-off before heading over to Grey’s Anatomy. Eventually, Walsh decided to depart Private Practice, resulting in the show ending with season 6. Walsh’s last appearance on Grey’s Anatomy was for an episode back in season 8 entitled “If/Then.” Since then, she’s co-starred in three Netflix series: The Umbrella Academy, Emily in Paris, and 13 Reasons Why.

Walsh is just one of the familiar faces that Grey’s Anatomy has recently brought back. Season 17 saw the return of fan-favorite characters such as Derek Shepherd (Patrick Dempsey) and George O’Malley (T.R. Knight) while Meredith Grey (Ellen Pompeo) was battling COVID. Kate Burton, who played Meredith’s mother Ellis Grey, also returned in the first episode of season 18 and is apparently booked in for multiple episodes. Undeniably, Addison has a history with Meredith, but the character she has the closest ties is actually Amelia. When Walsh bowed out of Private Practice in 2013, she had said she felt Addison’s journey was complete. Still, this led to an exciting fan theory (via Reddit), speculating that Addison will return because Amelia’s struggle with substance abuse will be brought back to the forefront in season 18.

During Amelia’s time on Private Practice, she struggled with multiple addictions, first alcoholism before switching to pills, and finally heroin. The fan theory is that Amelia rejected Link’s recent marriage proposal because she was going to relapse. This could be a possibility because while Amelia hasn’t relapsed in a recent episode, she struggled due to the pandemic. It may also be the reason for Addison’s return, as the character was close to her former sister-in-law and shared that bond that went beyond family obligations. Addison could help Amelia through her relapse and guide her back to sobriety.

Fans have long wondered what Addison has been up to in the Grey’s Anatomy universe. Since her departure, Addison has been mentioned once during season 11, episode 5, entitled “Bend & Break.” The reference occurred during a brief conversation between Amelia and Nicole Herman (Geena Davis) on how Addison enjoyed motherhood. It’s worth noting that this was the first mention of Addison since Grey’s Anatomy season 8, and it’s linked to Amelia suggesting the pair keep in touch and still have a close relationship. Addison has not been mentioned on the show since, and her absence was especially felt with Derek’s death, and even then, her reason to return to Seattle lay with Amelia.

While it stands to be seen why Addison decided to return to the halls of Grey Sloan Memorial Hospital, her relationship with Amelia is one of the longest-running relationships in Grey’s Anatomy history that spans the original show and the spin-off. The relationship between the two women is strong, and if anyone can help Amelia through a relapse in Grey’s Anatomy, it’s Addison.