Rachel Nichols has yet to appear on Criminal Minds in her character's planned guest-starring role, but she's already earned a promotion to full-time series regular.

Guess the producers really like what they see.

The former Alias star originally signed on for a three-episode arc beginning this week (Dec. 8) as Ashley Seager, an FBI cadet with an unusual family history.

Hotcher (Thomas Gibson) invites Ashley to help consult on a case.

It was previously unclear if Criminal Minds would bring on a new female series regular this year after the controversial exit of A.J. Cook in September, but it looks like they have.

Why the popular Cook would be let go for creative reasons is a mystery to many, especially without having seen what Nichols brings to the show. Her debut should be interesting.

Also this summer, Paget Brewster's role was reduced from 22 to 17 episodes, sparking rumors that the show was looking to kill off Prentiss or write her off in as it did with J.J.

Brewster was later asked to appear in all 22 episodes this year, but opted to work a reduced number so she could field other offers for future pilots/projects. It's all very odd.

What do you think of Rachel Nichols' hiring and the Criminal Minds casting shakeups?

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.