WARNING: 'NCIS' SPOILER ALERT! SCOOPS ON SEASON 13 FOLLOW!

"NCIS" left viewers with quite the cliffhanger last season when  Leroy Jethro Gibbs (Mark Harmon) was shot. When the show returns for its 13th season, Gibbs is rushed to an aircraft carrier in the Persian Gulf for surgery, and you may recognize his surgeon.

Jon Cryer.

For those who need their memories refreshed, in the Season 12 finale, Gibbs, Tony DiNozzo (Michael Weatherly) and CIA Officer Joanna Teague (Mimi Rogers), and the late agent Ned Dornegett's (Matt Jones) mother were in Iraq, trying to track down and put an end to the terrorist group The Calling. But before that happened, Gibbs was shot by Luke (Daniel Zolghadri), the teenager who had been a guest at Gibbs' home, who is a Calling recruit.

Cut to Season 13, which picks up right where 12 left off, and Gibbs is flown to a Navy ship, where he is operated on by a surgeon created in the image of Hawkeye Pierce and Trapper John from the TV series "M*A*S*H."

"I was a huge "M*A*S*H" fan growing up," executive producer Gary Glasberg told FOX411. "So the character was really inspired by all of those "M*A*S*H" characters that I grew up with. There's that cynicism, sarcasm and that use of humor to balance the reality of what they do."

Gibbs survives, but he doesn't emerge unscathed from his ordeal. The first half of the Season 13 premiere is about his surgery and meeting the doctor who helps him start on his journey of recovery. But halfway through, we fast forward to Gibbs is back in the office. We will watch him face some demons and make some new decisions -- maybe even some new rules.

"From the minute he steps off the elevator into the squad room, you're going to see a difference in who Gibbs is," Glasberg says. "You're going to see a difference physically in who he is and then as the show progresses -- especially at the end, there's a phenomenal scene between Gibbs and John Cryer, where we see him say things that are not the Gibbs that we're used to. It's not a drastic change, but it's enough for people who really know this character to say, 'This man's been to hell and back.'"

So as Gibbs makes changes in his life, will one of those possibly be a better haircut? "I'm not going to comment," Glasberg laughs. "The intent this season was to shake things up a little bit, to change things a little so that the actors have something fresh to play and something to look forward to, and we're doing just that. It's going to be a little different for the viewers, but it's still the 'NCIS' we know and love."

"I'm eager to see how people respond," Glasberg adds. "We're shaking things up a little bit. He's really embracing it and having fun with it. I'm eager to share it with everybody."

"NCIS" premieres on Tuesday, Sept. 22 on CBS.