Portugal spent the rest of the decade in either AAA or the majors.

In 1989, he went 7–1 with a 2.75 earned run average for them and won a spot in the starting rotation.

He had his best season in 1993, when he won 18 games, led the National League in winning percentage, and finished sixth in the Cy Young Award voting.

[2] Portugal signed with the San Francisco Giants as a free agent in 1994.

Typically a .200 hitter, he led all regular starting pitchers with a .354 batting average in 1994 and won the Silver Slugger Award.