I seriously want to cry.
How could he go?
He's one of the reasons i watch the show.
The other reason was her.
But then she's gone.
And he's going.
What's the point?
Why must he leave when i rediscovered my love for CSI once again?
Why must he go?
Why must my heart break for the third time?[Sara,Warrick and Grissom]
Why does this have to happen?
Why don't they just end the series after tying up the loose ends?
Why am i so sad?
Why are there so many whys?
Why do i always have to say goodbye?

Gil Grissom is saying goodbye.

According to Ausiello, the tenth episode of CSI: Crime Scene Investigation's ninth season will be the last appearance of William Petersen (Gil Grissom) as a full-time series regular on the series. However, that doesn't mean the audience has seen the last of Grissom. "Billy is leaving," said executive producer Carol Mendelsohn. "But he will remain throughout the run of the series an executive producer. And he will, whenever CBS asks, come back. I don't think you've seen the last of Gil Grissom."

"I'm in a great place in terms of knowing that I'll be more free to make choices. And I'm responsible enough to not do it in a way that would hurt [the show]," Petersen explained. "I want it to work for the writers, I want it to work for the cast, and, most importantly, I want it to work for the audience. I don't want them to abandon the show." The actor also pointed out that his decision to leave isn't a sign of deeper problems. "For me, it's a really good situation," he clarified. "I don't want the audience to think it's not... [It isn't] like there's something going on, like 'Petersen's unhappy,' 'cause it's not true. It's quite the contrary."

CSI lost Jorja Fox (Sara Sidle) last year, and Gary Dourdan's (Warrick Brown) departure was announced later on. With Petersen leaving, that means three original cast members will be gone from the show. "This will be a year of transition for the show," Mendehlson said. "We always knew it was coming, and I'm glad it didn't come until now." She went on to say, "There's never going to be another William Petersen, and there will never be another Jorja Fox. But we are not out to just replace those actors. We're out to add new characters to the show, and the show will change as a result. But that's a good thing."

Petersen's exit isn't the only thing coming up in season nine. Fox will be back as Sara for "multiple" episodes, according to Mendelsohn, and the Miniature Killer will be back to "cross paths" with Grissom. Director William Friedkin, a good friend of Petersen's, will also return to helm another episode of the series (after previously directing "Cockroaches")--this time the show's 200th episode. "Billy will definitely be on the set for Mr. Friedkin's episode -- whether it's behind the camera or in front of the camera is TBD," Mendelsohn said. "I don't think you'll be able to keep him away once he's back in L.A."

As previously announced, Lauren Lee Smith will join the show as Riley Adams, a new CSI. "She has a very distinct personality... a very wry sense of humor. She doesn't take herself too seriously," Mendelsohn explained, and executive producer Naren Shankar added, "This is a person who, unlike the rest of our gang, has not had Grissom as a mentor. So there's a very different relationship between Riley and Grissom."

Another new character to be added to the series won't be a criminalist to begin with. "He's a professor with background in pathology. He will appear when Grissom is investigating what will be a two-part case," Mendelsohn said. "He will help Grissom and the team bring the perpetrator to justice, and then this character will stay around and ultimately become a CSI." The character will have a rare genetic abnormality, and the show is seeking to cast a high-profile actor to fill the role.

One question that remains is how Grissom will leave the show. "I wouldn't want to say exactly what we're going do -- I want people to watch, certainly," Petersen said. "But Sara is involved... It's often darkest just before the dawn." The actor went on to say, "My biggest problem with leaving the show at any point isn't leaving Grissom -- I'm an actor, it's time to do other things. [The hard part will be saying goodbye] to the cast and crew. [So] I'm going to stay as involved as I'm allowed to be throughout the remainder of this show. Until they turn off all the lights."

Goodbye.