CSI showrunner Carol Mendelsohn has dropped new hints about Marg Helgenberger's forthcoming exit.
Helgenberger will depart her role as Catherine Willows later this month, after almost 12 years on the CBS crime drama.
"As a woman, Catherine feels she's hit a glass ceiling at CSI," Mendelsohn told TV Guide. "It's something that's been weighing on her, and she sees a door to a new life."
She added that Catherine will be inspired to move on after working a case with an old friend (Annabeth Gish) who works at the FBI.
"These FBI agents shine a mirror on how good she is at what she does," revealed the executive producer.
However, fellow executive producer Don McGill confirmed that Helgenberger is welcome to return to CSI in the future.
"It's not a 'for always' goodbye," he said. "There's always an open door."
Helgenberger recently admitted that she "felt the need to... step back" from her CSI role.
"I had been playing this character for 11 and a half years," she explained. "I'm... very excited about the great wide open, the future and all the possibilities."
Back to the Future actress Elisabeth Shue will replace Helgenberger as a series regular.
CSI returns to CBS tonight at 10/9c.
> CSI Marg Helgenberger interview: 'I do feel compelled to leave now'
Watch a promo for the return of CSI below: