Derek Mann is a guest character on Frasier. He is voiced by Joe Mantegna.
Mann is a Seattle columnist who writes an article entitled "I Hate Frasier Crane" - which was in fact the entirety of the article. Frasier complains over the air that his prose lacks substance, and that he had no good reason behind his statement. Mann gets angry and challenges Frasier to a physical fight on the air. Frasier ultimately decides to go through with it, but the police break up the fight before it can begin.
- He is not seen, but it is strongly implied he was much larger than Fraiser.
- The character is also briefly mentioned in the episode "The Botched Language Of Cranes", as he criticizes some advice Frasier gave one of his callers.