Baker will play Sam Paley, a maverick politician from the Southwest who is leading an aggressive investigation into the Keane administration, according to The Hollywood Reporter.
"Homeland", toplined by Claire Danes, recently added Morgan Spector and Mackenzie Astin to its upcoming season as well.
Production of the new installment started up on September 11 in Richmond, Virginia, with plans for the Fox 21 Television Studios-produced series to premiere on Showtime in early 2018.