The actress has reportedly been axed from the crime drama after five years, with a source telling TVGuide.com she has been dropped for "creative reasons".
But devotees are not happy about her exit and more than 12,000 fans have signed a petition calling for executives at CBS to reverse the decision.
Cook has now thanked fans for their devotion with a post on her Twitter.com page, writing, "Your kind words and support have made me feel wanted and loved!"
Cook's castmate Paget Brewster has also addressed the controversy.
In a post on her Twitter.com blog, she writes, "'Creative reasons' has been an executive bulls**t excuse for DECADES. It IS financial. AJ is a dreamboat. And yes, I am hurt, too."
Please sign the petition at http://www.petitiononline.com/cmwomen/petition.html
Call Nina Tassler's office and tell her what you think about AJ Cook's and Paget Brewster's unfair treatmentt: 818-655-1400