After one season with the A's, Sanguillen was traded back to the Pirates for Miguel Diloné and Elías Sosa. He played in only 85 games in 1978, mostly as a first baseman as Ed Ott and Duffy Dyer platooned at the catcher's position. His playing time diminished further in 1979, playing in only 56 games, although he contributed a two-out, game-winning single and RBI for the Pirates in Game 2 of the 1979 World Series against the Orioles. The 1980 season was Sanguillen's last in the majors, although he returned in 1982 to play in the Mexican League.