Cook played JJ in the series but was controversially dropped from the show before the current season began.
She returned for two episodes to wrap up her storylines and appeared in her co-star Paget Brewster's final episode.
TV Line reports that Cook is now in negotiations to return as a series regular on Criminal Minds next season.
Reports have already suggested that the show's producers want Brewster to return if her pilot My Life As An Experiment is not picked up.
Talks are thought to be ongoing with male cast members Thomas Gibson and Shemar Moore, who have not yet signed up for the new season.
Meanwhile, showrunner Ed Bernero has reportedly told the cast and crew that he has decided to leave. Bernero, who is currently working on a pilot for ABC, is expected to be replaced by executive producer Erica Messer. The news comes shortly after fellow showrunner Simon Mirren decided to step down.
Criminal Minds airs on Wednesdays at 9/8c on CBS.
> Criminal Minds star 'understands criticism'