TVLine.com made a bold announcement today on their te when they broke the news that Colin Hanks would be joining the cast of Dexter for a major arc in Season x.

Showtime hasn't provided any specifics as to what Hank's role will be but they did announce that three reoccurring roles were going to be cast;
Jamie: Described as an outgoing and fun Latina in her mid-20s, this Florida native relocates to Miami for grad school.
Chicago Mike: New thirtysomething African-American homicide detective who possesses a finely tuned "Bull Shit" detector. The Windy City native does not play well with others.
Louis: A buddy of Masuka’s (C.S. Lee) who joins MMP as a new lab intern. Role calls for a Caucaan actor in his 30s who is “attractive in his own way.”
Hanks, isn't believed to be cast for any of these roles, but it's posble that he'll play an adversary to Dexter.