'Grey's Anatomy' Season 16 Cast: Who Is Leaving, Who Is Returning and Who Got Promoted?

The 15 seasons of Grey's Anatomy that have aired so far have seen dozens of doctors come and go from the cast, with many guest stars rising through the ranks to become main characters. And Season 16 is no different.

The new season of the ABC medical drama starts Thursday and will see three cast members promoted to series regulars. The makers of Grey's Anatomy have also teased that a major star from the past may be returning before the season ends.

Who Got Promoted to the Main Cast of Grey's Anatomy for Season 16?

Season 15 ended with a trio of doctors, including lead Meredith Grey (played by Ellen Pompeo), getting fired after taking the fall for medical insurance fraud, and there are a lot of resulting changes in the ranks of Grey Sloane Memorial Hospital.

Though Meredith, Alex Karev (Justin Chambers) and Richard Webber (James Pickens Jr.) will not be leaving the ABC series, their absence may allow for some promotions in the hospital and in the Grey's Anatomy cast. Doctors Levi Schmitt (Jake Borelli), Atticus Lincoln (Chris Carmack) and Thomas Koracick (Greg Germann) will join the main cast for Season 16, following their guest appearances on the show.

Showrunner Krista Vernoff confirmed the actors' promotions to Deadline.

"Chris, Jake, and Greg have been recurring for us as guest stars and have popped as fan favorites," Vernoff said. "We are excited to continue revealing their characters, and we are beyond thrilled to welcome them to the Grey's Anatomy family."

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Ellen Pompeo has been contracted for "Grey's Anatomy" Seasons 16 and 17. ABC

Who Is Returning to the Cast of Grey's Anatomy Season 16?

At a Television Critics Association event, Vernoff teased that a star who has left the series might make an exciting return.

"I'm trying to get someone back," she said. "There's someone I'm hoping will make an appearance this year, [but] it's a real maybe. I'm trying."

Vernoff refused to reveal the name of the former cast member she was chasing to appear—though this did not stop fans speculating. Their suggestions included characters like Christina Yang (Sandra Oh), Callie Torres (Sara Ramirez) and Addison Montgomery (Kate Walsh).

Oh, however, told Digital Spy that she will not be returning, now she is part of the cast of Killing Eve.

"I'm not coming back," she said. "So much love and gratitude for that time, but I have a new love in my life now. And I want to hang out with her."

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Jake Borelli has been promoted to a series regular as Levi Schmitt on "Grey's Anatomy" Season 16. ABC

Is Anyone Leaving Grey's Anatomy Season 16?

So far, no big cast members have announced they are leaving Grey's this year.

One person who will definitely not be leaving is Ellen Pompeo, who recently re-upped her contract for Seasons 16 and 17.

After some controversial cast departures, the Grey's Anatomy cast has been fairly static recently, with no major departures since the end of Season 14, when April Kepner (Sarah Drew), Arizona Robbins (Jessica Capshaw) and Nathan Riggs (Martin Henderson) all exited the show.

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The casts of "Grey's Anatomy" and "Station 19" will cross over this season. ABC

Are There Any New Cast Members for Grey's Anatomy Season 16?

No major new doctors are joining Grey Sloan this year, but ABC has revealed the show will feature some cast members from another of their series, as well as a reunion of actors from Charmed.

Following a successful crossover earlier this year, the worlds of Grey's Anatomy and Station 19 will become a "unified universe," according to Vernoff in an interview with TVLine.

At the ABC upfronts, Entertainment President Karey Burke said we can expect to see the firefighters of Station 19 making regular appearances. "People can expect crossover event between these series every week," Burke said.

Season 16, Episode 3, meanwhile, will feature Charmed stars Alyssa Milano and Holly Marie Combs as squabbling sisters.

The episode will air as part of ABC's "Cast from the Past" week featuring cast and creative teams reunite on new shows. In this case, Milano and Combs will reunite with former Charmed writer Vernoff.

Grey's Anatomy Season 16 airs Thursdays at 8 p.m. ET/7p.m. CT on ABC.