Hamilton led the NL in walks in his rookie 1962 season and was 7-12 as a starter. His 1.95 ERA in 15 relief appearances showed promise, so he saw most of his subsequent action out of the bullpen. After spending most of 1965 on the DL with the Tigers, he was sold to the Mets for 1966 and had a career-high 13 saves. That May 4, he pitched an 8-0 one-hitter against the Cardinals; the only hit was a third-inning single by the opposing pitcher, Ray Sadecki. Traded to the Angels in mid-1967, he returned to starting and went 9-6, 3.25 for them the rest of the way. It was his best season, but it was marred in August when he hit Tony Conigliaro in the face with a pitch, nearly blinding him and curtailing a great career.