"Criminal Minds" fans will notice several changes on the long-running police drama series when it returns to CBS in the fall.

For one, executive producer Erica Messer confirmed Jennifer Love Hewitt will not reprise her role as FBI Undercover Agent Kate Callahan since she is pregnant in real life and has taken take time off for maternity leave.

In addition, series star AJ Cook revealed that she, too, is pregnant during the Season 10 finale. As a result, Messer revealed that her character, JJ, won't be featured in the first couple of episodes of the new season since Cook will be on leave. Instead, the show will find a way to write around her maternity leave while she is gone.

During an interview with TV Guide, the executive producer said that rather than introducing a new character to replace Kate, they are toying with the idea of bringing back familiar faces to guest star or continuing the "revolving door" of new agents.

Although Messer didn't name any of the familiar faces who will potentially reemerge in the new season, actor Joe Mantegna dropped a spoiler about one actress who may reappear on the show next season. According to Crossmap, Mantegna, who plays Senior Supervisory Special Agent David Rossi, hinted that Paget Brewster may reprise her role as Supervisory Special Agent Emily Prentiss.

"Well, there's been talk of -- there's a chance Paget may make an appearance now and again. Eric our producer mentioned it in an interview that there's a possibility that Paget may return from time to time," the 67-year-old actor said. 

As fans may recall, the last time Emily Prentiss appeared on the show was in Season 9 when she assisted the special FBI agents in finding JJ after she went missing.