This man is the only person in the Hall of Fame to hit a home run in his first MLB at bat, the only home run he would hit in his 21 year career. Of the nine teams this man played for, his six seasons with the Sox was the most of any team. Of all pitchers to pitch entirely and retire after 1920, only Mariano Rivera has a lower career ERA. Identify this Hall of Fame pitcher generally credited as the first relief pitcher to get sent to Cooperstown.
James Hoyt Wilhelm