After languishing in the minors, Wilhelm stuck with the Giants as a twenty-nine-year-old rookie and made a sensational debut in 1952, going 15-3 with 11 saves. He led the league in won-lost percentage (.833) and ERA (2.43) to become the first rookie ever to top his league in those two categories and the only rookie ever to win an ERA crown. Wilhem also holds the distinction of being the first relief pitcher elected to the hall of fame.