Rachel Nichols Rachel Nichols

Former Alias star Rachel Nichols has been tapped for a multi-episode arc on Criminal Minds, a show rep tells TVGuide.com

Nichols will play FBI cadet Ashley Seager, who's invited by Hotch (Thomas Gibson) to consult on a case after learning her family history will bring a unique insight into a serial killer's mind.

Criminal Minds: How will the team deal with the loss of JJ?

Nichols' character was originally conceived as a replacement for departing cast member A.J. Cook's JJ, according to Deadline, which first reported Nichols' casting. However, Nichols' role has since been reduced to a three-episode arc to air later this season. Cook's last episode airs Wednesday.Nichols, who played computer genius Rachel Gibson on the fifth season of Alias, has also appeared in such films as P2, Star Trek, and G.I. Joe: The Rise of Cobra.