When Madam Secretary returns for its abbreviated sixth and final season on CBS, it will be without Sara Ramirez, who will not be returning as a series regular, Deadline has confirmed. Ramirez, who plays political strategist Kat Sandoval, may return for a guest appearance, according to TVLine, which first reported the casting news. Ramirez has been with the political drama series since season four.

Ramirez joined the series following the sudden departure of Bebe Neuwirth who played Nadine Tolliver. Ramirez’s Kat Sandoval is legendary in D.C. for her talent and for abruptly dropping out of politics until Elizabeth (Téa Leoni) managed to coax her back into the State Department.

Madam Secretary was Ramirez’s first series regular TV role since her departure from ABC’s Grey’s Anatomy, where she appeared for over a decade as Dr. Callie Torres. Her previous credits include voice roles on Disney Jr.s’ hit animated series Sofia the First and Vampirina. Ramirez previously won a Tony Award for her performance in Monty Python’s Spamalot.

In addition to Leoni, Madam Secretary stars Tim Daly, Zeljko Ivanek, Keith Carradine, Sebastian Arcelus, Patina Miller, Geoffrey Arend, Erich Bergen, Kathrine Herzer, Wallis Currie-Wood and Evan Roe.

Barbara Hall, Lori McCreary, David Grae, Eric Stoltz and Morgan Freeman are executive producers for CBS Television Studios in association with Revelations Entertainment.

Madam Secretary season 6 premieres in October on CBS.