The Red Sox took a 1-0 series lead with an 8-4 win over the Los Angeles Dodgers in Game 1 on Tuesday night in Boston.
Pomeranz gives the Red Sox another matchup left-hander to use against the Dodgers. He made 11 starts, then was sent to the bullpen in August and had a 5.96 ERA in 15 relief appearances, striking out 22 and walking 12 in 22⅔ innings while allowing 27 hits.
Workman appeared in three games in the postseason and gave up seven hits and five earned runs -- including two home runs -- in one inning of a Game 1 loss to the Houston Astros in the American League Championship Series.
There had been some thought that knuckleballer Steven Wright, who threw a simulated game Sunday, might be sufficiently recovered from a recurrence of his left knee injury to return for the World Series, but he's not on the roster.
Ferguson, a rookie, appeared in six postseason games, facing a combined 10 batters, retiring nine and walking one.
Alexander led the Dodgers in appearances in the regular season but was left off the roster for the NLCS against the Brewers. He pitched one inning against Atlanta in the ALDS.
The Associated Press contributed to this report.