The actress recently confirmed that the show's 12th season will be her last, with her character Catherine Willows only expected to appear in the first 12 episodes.
"The final case that Catherine will be involved in will actually put her and her family and the people that she cares about in jeopardy," executive producer Carol Mendelsohn told TV Guide.
The showrunner added that Willows will become an "action hero" in her final CSI appearance.
"Catherine won't just take it lying down, for sure," she said. "She'll take matters into her own hands and get to the truth."
It was previously confirmed that Laurence Fishburne will not return to CSI next season, with Ted Danson joining the cast as new lead investigator DB Russell.
The new season of CSI premieres on Wednesday, September 21 on CBS.
> William Petersen 'could still return to CSI'
Watch a clip from CSI's 11th season finale below: