Why is Olivia Wilde (Hadley) credited in 7x16 Out of the Chute?

Her name was in the credits, and she's credited on a href="http://www.imdb.com/character/ch0041162/filmoseries#tt0412142" rel="nofollow"http://www.imdb.com/character/ch0041162/…/a but she does not appear to have actually been in the show. She's apparently due back in a couple episodes... Did I miss something?