After rehabilitation, he re-joined the Expos in  but still displayed steady showings of his All-Star form, earning a career-high 12 wins and leading the majors with five shutouts. After several productive months into the 1998 season, Pérez was traded to the Los Angeles Dodgers on July 31 along with Hiram Bocachica and Mark Grudzielanek for Peter Bergeron, Wilton Guerrero, Ted Lilly, and Jonathan Tucker.
Following rehabilitation, he rejoined the Expos but continued to perform at an All-Star level, setting a career high of 12 wins and leading the league in shutouts.  After several successful months into the 1998 season, Pérez was traded to the Los Angeles Dodgers on July 31 along with Bocachica and Grudzielanek for Bergeron, Guerrero, Lilly, and Tucker.