Fans of CBS' hit series NCIS should expect a major shift in season 13 as Michael Weatherly, who portrays Tony DiNozzo, revealed that the upcoming episodes would showcase how the show metamorphosis into major changes never before witnessed by the viewers.

Speaking with TV Fanatic in West Hollywood at the CBS Television Critics Association party about the forthcoming season of NCIS, Weatherly added that his team will struggle dealing with the shooting of NCIS Special Agent Leroy Jethro Gibbs (Mark Harmon) in the hands of a young boy he befriended in a terrorist attack investigation in Afghanistan.

He spoke of the changes, "Every two years, say, you go through these revolutions and when Sasha [Alexander, who portrayed Kate Todd] left at the end of Season 2, revolution. Lauren Holly [who portrayed Director Jenny Shepard] left after Season 5. Cote [de Pablo, who portrayed Ziva David] left after Season 10, big changes do require a recalibration and right now the show is undergoing kind of a metamorphosis that isn't because of anything external but more of an internal change for the first time."

The shooting of Gibbs will play a key role in the internal changes, Weatherly explained.

He further commented on the upcoming NCIS Season 13, "I think there's something fundamental shifting," adding that the new episodes would delve into Gibbs inability to move on and get stuck in the past.

"He has no wife, no partner, he's living with all these ghosts and I get a little tired of it sometimes but the truth is I think what that message is that's really sent to the audience is that Gibbs can't move on. He's trapped," Weatherly added.

It definitely makes for an interesting season to examine all of this stuff that has built up over the course of the series.

Gibbs Returning in Season 13

Contrary to earlier speculations, Gibbs will survive the shooting. Proof of this is the signing of Hamon of new contract reprising his role in NCIS, reported Kpopstarz.com.  But his road to recovery will be long and the wounds he sustained will also have "psychological ramifications."

Showrunner Gary Glasberg dished out additional spoilers as reported in TV Guide quoting him as saying, "Gibbs is in a difficult place, a physically difficult place. ... We're still functioning as a team, but there's absolutely some conflict.

 "There's issues that have to get worked out between team members, very specifically between Tony and Gibbs. ... It's tricky, and they're sensitive to what he's going through, and they're trying to be there for him as coworker and as friend and as family member. They're being ultra-supportive of him," he added.

Despite what happened with Gibbs, season 13 of NCIS will be action-packed with the team in  full swing. One character will stand out and become the "glue" that will hold the NCIS team together and help them get through the challenging road ahead in "NCIS" Season 13: Jimmy Palmer.

Palmer, played by actor Brian Dietzen, is the assistant of NCIS Chief Medical Examiner Donald "Ducky" Mallard (David McCallum). In the previous seasons of NCIS, Palmer had been relegated to relatively minor roles. His appearances in the NCIS team meetings had been quite limited as well. With the return of the TV series, however, Palmer finds himself playing a major role in the NCIS team in terms of helping the agents iron out their differences and keeping the peace in the office.

"Jimmy Palmer is some of the glue that keeps the characters together - meaning he's the confidant, he's the friend," shared Dietzen in an interview with TV Guide. He added, "But by the end of the year, his friendships versus his professional obligations are really going to be tested, specifically with DiNozzo. That friendship will be super-tested."

The official release date of NCIS is on Sept. 22 at 8 p.m. ET at CBS.