There are several articles online about Laurence Fishburne possibly joining CSI when Billy leaves.
This one from the Hollywood Reporter
Laurence Fishburne is prime ‘CSI’ suspect
In talks to succeed William Petersen as star of the series
Laurence Fishburne is in talks to succeed William Petersen as the star of CBS’ veteran crime drama “CSI: Crime Scene Investigation.”
CBS and CBS Par’s search has been shrouded in secrecy, but sources say Fishburne is being heavily courted to play the new character, described as a doctor/scientist outsider to the CSI unit who has the same genetic profile as a serial killer but hasn’t previously acted on any homicidal impulses.
Fishburne, an Oscar nominee for “What’s Love Got to Do With It” who most recently co-starred in “21,” had been mentioned as one of the “CSI” producers’ top choices for the role, along with John Malkovich and Kurt Russell.