Know Me Al by Ring Lardner.
This profession is practiced by Jack Keefe, the protagonist of You Know Me Al by Ring Lardner. Don DeLillo recounts a story about people with this profession in "Pafko at the Wall," the prologue to his novel Underworld. Bump Bailey is a character with this profession. W.P. Kinsella often wrote about men who play this game for a living. A poem about this profession claimed "Cooney died at first" and is by Ernest Thayer. For 10 points, name this athletic profession held by Roy Hobbs in The Natural and the title figure of "Casey at the Bat."
This profession is practiced by Jack Keefe, the protagonist of You
baseball players [prompt on athletes]