Sandy Koufax. He wasn't terrible. In a 6-year run starting in 1961 Koufax was won 129 games, losing only 47, leading the league in ERA 5 times, FIP every year, shutouts three times and strikeouts on 4 occasions. He also had the best WHIP in four years, H/9 innings and K/9 innings five times and in strikeout/walk ratio three times.
Sandy Koufax / played his entire MLB career for the Brooklyn/Los Angeles Dodgers, from 1955 to 1966. He retired at the peak of his career, and in 1972 became the youngest player ever elected to the Baseball Hall of Fame (36). Koufax's career peaked with a run of six outstanding seasons from 1961 to 1966, before arthritis in his left elbow ended his career prematurely at age 30. Koufax was the first major leaguer to pitch four no-hitters (including a perfect game). 3 Cy Youngs and 1 MVP.