With A.J. Cook departing 'Criminal Minds,' the series is adding another female character: Rachel Nichols will join the cast for a three-episode story arc later this season.

According to Deadline Hollywood, Nichols will play FBI cadet Ashley Seager. Look for Agent Hotch to invite the young cadet to consult on a case because of her family history.

The role was originally conceived as a series regular part, but has since been downgraded.

In other casting news ...

• Catherine Dent will guest star on 'NCIS.' Dent will play a former NCIS agent who has a past with Ducky. Look for 'The Shield' alumna to appear in at least two episodes in November. [Ausiello Files]

• Anna Kournikova will appear on NBC's 'Biggest Loser' on Tue., Oct. 5. The tennis pro will put the remaining contestants through a workout challenge that turns into a battle of the sexes. [TV Guide]