Zahn was a minor contributor to the Dodgers’ 1974 NL pennant, going 3-5 with a 2.03 ERA in spot starts and relief. Traded to the Cubs in May 1975 with pitcher Eddie Solomon for Burt Hooton, he spent most of the rest of the year on the DL and was released by Chicago after a disappointing 1976, during which he had bone fragments removed from his elbow. Picked up by the Twins, he used a hard slider to become one of their more reliable starters, winning 12-14 games each of four straight years (1977-80) for mediocre teams. He joined California as a free agent for the 1981 season and had his best season in 1982. He was 18-8 with a 3.73 ERA and finished sixth in the Cy Young Award voting as the Angels won the AL West. Zahn was hit hard by the Brewers in his Game Three start in the LCS and took the loss. In 1983 he lost a month to an inflamed shoulder, stopping his six-year string of victories in double figures (he finished 9-11). He rebounded to go 13-10, 3.12 in 1984, but arm miseries cropped up again in 1985 and ended his career.
