He left the Angels via the 1968 Major League Baseball expansion draft and joined the Seattle Pilots, which later became the Milwaukee Brewers in 1970. In Milwaukee, Pattin finished with a 14–12 record and a 3.39 ERA in 37 games (29 starts) in 1970, and was named an All-Star in 1971, when he finished with a 14–14 record and a 3.13 ERA in 36 starts.
He left the Angels via the 1968 Major League Baseball expansion draft and joined the Seattle Pilots, which later became the Milwaukee Brewers in 1970. In Milwaukee, Pattin had a 14–12 record with a 3.39 ERA in 37 games (29 starts) in 1970, and was named an All-Star in 1971, when he finished with a 14–14 record and a 3.13 ERA in 36 starts.