Erskine broke into the majors a year before Don Newcombe, and from 1948–50 was used primarily as a reliever, going 21-10. In 1951, he mixed 19 starts with 27 relief appearances, and went 16-12. Erskine was 14-6 in 1952 with a career-best 2.70 earned run average, then had his 20-win season in 1953, leading the league with a .769 winning percentage along with 187 strikeouts and 16 complete games, all career highs. This was followed by 18-15 in 1954, posting career highs in starts (37) and innings (260-1/3), then by 11-8 in 1955 and 13-11 in 1956.