NCIS Season 17 is scheduled to premiere next week. Fan-favourite Naval Criminal Investigative Service agents Leroy Jethro Gibbs (Mark Harmon), Timothy McGee (Sean Murray), Nick (Wilmer Valderrama), Ellie (Emily Wickersham) and others will get back to action after a long hiatus. Meanwhile, things may not be too good for our main man Gibbs. A recent fan theory suggests that the show might be preparing for Harmon's departure.

According to Pop Culture, there might be a major cast shakeup on the way. A popular fan theory is reportedly making the rounds on Reddit and other social media platforms. As per the theory, this might be Gibbs' last season and Cote De Pablo's Ziva David's return might have something to do with it.

It is said that the much-admired character might be returning as Gibbs' replacement. Ziva, who was sorely popular among the fans and is much younger than Gibbs might be a great fit for Gibbs' replacement in the agency and the series.

The user on Reddit attributed the possible change in the cast to Gibbs' old age.

"Gibbs is old now, I stand by that the only way this show can continue is if Ziva takes his place as team lead, oh how wonderful that would be. They could just write that for her child's protection Tony is taking care of her in hiding, I wouldn't be mad at all, anything to have her back," the Reddit user wrote.

By the look of the latest trailer for "NCIS" Season 17, it is clear Gibbs is in danger. As revealed by Ziva, a woman called Sahar is coming to kill him.

What makes the theory more believable is that Harmon's contract is set to end after "NCIS" Season 17. There is no news of renewal which has led to speculations of his exit from the show.

Ziva first appeared in "NCIS" season 16 finale. She appeared at Gibbs' house warning him about the danger he is facing. However, it wasn't made clear whether it was really Ziva or it was Gibbs hallucinating of her ghost.

Meanwhile, the trailer reveals that Ziva is alive and will be back to save Gibbs. For three years, the team thought that Ziva is dead, but it leaves everyone in a shock when they find out about her return.

Fans are advised to take this information with a grain of salt. The report lacks comments from the associated persons and is mere speculation.

Mark Harmon
Mark Harmon as Leroy Jethro Gibbs in NCIS series CBS

Speaking with TV Insider, Cote De Pablo revealed the reason for her return to the series.

"She feels responsible for her father figure, Gibbs, and has to save him," she said.

"NCIS" Season 17 premieres with episode 1 titled "Out of the Darkness" on Tuesday, September 24 on CBS.