Williamson led the Pacific Coast League
with 16 saves for Las Vegas in 1986, then was traded to the Orioles by the Padres with Terry Kennedy
for Storm Davis
. He made
61 appearances for Baltimore as a rookie in 1987 (an Orioles rookie record), and was in the starting rotation briefly in 1988, but was returned to the minors with a 5-8, 4.90 record.
Returning to the bigs in 1989, Williamson settled into a middle-relief role for the Birds, posting stellar 2.93 and 2.21 ERA's in back-to-back seasons. Having found his niche as a reliever, he started only three games after 1988.