Even Mark Harmon doesn't appear to be certain about what may happen to Jethro Gibbs.

Appearing on a recent episode of the "The Late Show With James Corden," Ecumenical News reports the long running "NCIS" star told the host the show "births characters leaving."

Many have wondered what they can expect from the new season given the cliff-hanging way Season 12 ended. In that episode, Gibbs, Tony (Michael Weatherly) and Joanna (Mimi Rogers) were all in Afghanistan in search of the terrorist group responsible for the killing of Agent Dormeget (Matt Jones).

During the last few minutes of the show, Gibbs suffered at least two gunshot wounds at the hands of Luke, the boy he befriended and had been desperately trying to save. It's left many wondering if this is where it all will end for Harmon's grizzled character.

"It's not my choice, number one, but I think anybody is replaceable," he told Corden.

Previously "NCIS" executive producer Gary Glasberg told the "Hollywood Reporter" that show creators have "a lot of questions that need to be answered and then some impending danger that we need to deal with when we get back."

Glasberg also told Hollywood Reporter, "Regardless of the outcome, any time that Gibbs or one of our family members is in danger or injured, it significantly affects everyone. We'll have to see the long-term effects and the psychological effects, but they'll undoubtedly, as they always are, be there for each other. Then we'll see where it takes [us] as we move forward to the coming episode."

What that all means, seems anyone's guess, but with Gibbs down, DiNozzo will almost be certainly taking the lead in Afghanistan and on the case.

"NCIS's" Season 13 is expected to be back on air in September.