"CSI: Crime Scene Investigation" will indeed see the last of William Petersen as Gil Grissom in the series' first episode in 2009. Through a recently-outed press release, it has been unraveled that the bowing out of Peterson has been embedded in the forthcoming episode entitled "One to Go" as his character takes a sudden leave from the CSI team.
On the episode scheduled to air on Thursday, January 15, 2009, Peterson's character will stun his co-workers with an announcement that his time as a CSI has come to an end after working with Dr. Raymond Langston on the "Dick & Jane" murders. Before leaving the team for good though, he offers Langston a permanent position on the CSI team.
"One to Go" will see show's regulars, Marg Helgenberger, George Eads, Paul Guilfoyle, Eric Szmanda and many others. It will also feature the newest cast addition Laurence Fishburne as Dr. Raymond Langston. The episode directed by Alec Smight is written by executive producers, Naren Shankar and Carol Mendelsohn.
Reports on Peterson leaving the show has been broken out in July 2008 by Carol Mendelsohn and Naren Shankar. It was mentioned that though he won't be the series' regular anymore, he has agreed to return for occasional guest appearances. He will also remain being the series' executive producer.