On May 17, "NCIS" will bid goodbye to Michael Weatherly's Special Agent Anthony DiNozzo. After 13 seasons, the actor did not renew his contract and has, in fact, signed on for the starring role in the CBS pilot, "Bull."

So, with Weatherly moving on, the question of the day is: Will DiNozzo be killed off? Or will he leave Washington, D.C. and travel to Israel where he will be reunited with Ziva? Or something else entirely?

FOX411 spoke to "NCIS" showrunner Gary Glasberg to get the answer.

"I will say to you to expect Tony to be around for the whole final episode and enjoy the roller coaster ride that comes with it," Glasberg says.

But he tempers that by adding that Tony's relationship with Ziva absolutely has an impact on his reason to depart, which, hopefully, means Tony will be alive at the end.

"Ziva is a huge part of who Tony is," Glasberg did say. "There's no denying that. As we look back at 13 seasons of television, is there an element that involves Ziva? Absolutely. She's a huge part of who he is moving forward."

And even though Glasberg would not confirm nor deny whether or not Cote de Pablo, who played Ziva, would be returning for a final episode. De Pablo, herself, did tell members of an audience at a Q&A for the film The 33 that she does not return for DiNozzo's final episode.

Tony's departure comes as NCIS, Homeland and the FBI are dealing with a very lethal case. Former MI6 agent Jacob Scott is still on the loose and killing the people whose names are on the list of NCIS agents responsible for his wife's death. He has already assassinated Homeland Senior Division Chief Tom Morrow, and there is more death to follow.

So, when we return with a new episode on May 3, NCIS Director Leon Vance and Senior FBI Agent T.C. Fornell head to London to coordinate capturing Scott and returning him to prison.

The case is also how we will meet two potential new cast members: FBI Special Agent Tess Monroe (Sarah Clarke) and MI-6 Officer Clayton Reeves (Duane Henry).  

"Tess is brought in on the case and she works closely with Fornell and NCIS," Glasberg says. "Sarah Clarke has been fantastic. The character is direct and funny and quirky and physical, and she's been around the block. It's really fun in what feels like an organic character to kind of fall into our family."

On the other hand, Reeves is a fiery, edgy, MI6 agent, who is assisting with the manhunt on behalf of the Brits.

"Reeves is a young guy who comes from a working class British background, who has risen to this level in his agency and in this job," Glasberg says. "Still, there's a grit and an energy and a dirtiness that is under the surface. Duane Henry has just been fantastic. His enthusiasm and his smile light up a room. So both of those characters come into play in Episode 305, 'Dead Letter.' It adds to the energy and momentum of the manhunt."

Whether or not either Clarke or Henry will become series regulars is still up in the air. And while it seems unlikely at first that NCIS would bring in someone from MI6, it is not without precedent. After all, Ziva was Israeli Mossad.

"I don't know the answer because I haven't even seen the episodes cut yet," says Glasberg, who also says that no one can really replace Michael Weatherly. "You get a feel for things; you get a sense of things. You see how it's going. I can tell you from a work standpoint, they've been amazing. We have to see how it continues."

One thing that Glasberg does know for fact is that the "Family First" Season 13 finale episode has the largest guest cast that they have ever had on an episode of "NCIS."

"It is fitting in its farewell to Tony," he says. "Everybody from Robert Wagner to Joe Spano to Laura San Giacomo will be back. It is really one person after another after another. The vibe on the set has been fantastic. Every day has been unique."

"NCIS" returns with new a episode on May 3 on CBS, the first of the final three episodes of the season.