According to Bloody Disgusting, the Superman Returns actor will join the already cast Andrew Lincoln and Jon Bernthal in the series.
The Walking Dead, produced by Frank Darabont, is based on the Image comic venture by Robert Kirkman and Tony Moore.
The series follows police officer Rick Grimes as he leads a band of survivors as they attempt to stay alive after a zombie apocalypse.
The report did not offer any details about Routh's possible role.
Routh recently completed a recurring arc on NBC's Chuck.
Production on The Walking Dead begins in June in Atlanta.