Between the majors, minors and winter league play, Alvarez pitched close to 300 innings in 1991; an extremely heavy workload. In 1993 he managed to break into the Sox starting pitching rotation permanently. That season, Alvarez won 15 games and finished second in the league in earned run average, but he experienced control problems and led the league with 122 walks.
In 1994, Alvarez went 12–8 and made the American LeagueAll-Star team. After a disappointing 8–11 in 1995, he had 15 wins and 181 strikeouts in 1996.
In his first season with the Devil Rays Alvarez missed two months with tendonitis in his shoulder, eventually losing 14 games during the season. The following year he made two trips to the disabled list. Finally, he had arthroscopic shoulder surgery and missed the next two seasons. After finishing his contract with Tampa Bay, Álvarez signed with the Dodgers. He began the 2003 season as a starter for Triple-ALas Vegas. After going 5–1 with a 1.15 ERA, he filled the long relief role for the Dodgers at mid-season. Later he got a chance to start, collecting a 5–0 record and 1.06 ERA over a stretch of nine games. In 2004, he went 7–6 in 40 games (15 as a starter).
On August 1, 2005, Alvarez announced he would retire after the season. He compiled a career 102–92 record with 1330 strikeouts and a 3.96 ERA in 1747.2 innings.
^Baltimore Orioles (February 8, 2019). "Orioles Announce 2019 Minor League Coaching Staffs". PressBox Online Baltimore (Press release). Retrieved April 12, 2019. Former Major Leaguer WILSON ALVAREZ returns for his seventh season as Pitching Coach for the GCL Orioles.
The ESPN Baseball Encyclopedia – Gary Gillette, Peter Gammons, Pete Palmer. Publisher: Sterling Publishing, 2005. Format: Paperback, 1824pp. ISBN1-4027-4771-3