Lefty Jose Alvarado was added to the club's 28-player active roster for the championship series. He had been on the 45-day injured list since August because of shoulder inflammation. Alvarado, 25, in his fourth season with the Rays, has a 3.46 career ERA and 15 saves.
Alvarado did not pitch for the Rays during last season's ALDS series against Houston, which the Astros won in five games.
To make room for Alvarado on its 40-man roster, Tampa Bay designated reliever Oliver Drake for assignment. Drake, 33, made one scoreless appearance for the Rays against the New York Yankees in the ALDS but had to be replaced on the roster after suffering a right flexor tendon strain.
The Rays also added reliever Josh Fleming to their roster, giving them 14 pitchers and 14 position players for the showdown with Houston. Fleming, 24, was 5-0 with a 2.78 ERA in seven games during the regular season, working as both a starter and reliever.
Outfielder Brett Phillips was dropped from the Rays' ALCS roster. Phillips, 26, picked up from Kansas City in a midseason trade, was 0-for-2 over four appearances during the first two rounds.
Houston carried 14 pitchers and 14 position players for the ALCS, adding reliever Chase De Jong to the roster. Outfielder Chas McCormick was dropped to make room for De Jong.
The Astros carried McCormick, 24, on their roster for the first two rounds though he has yet to appear in a regular-season game at the big league level. He did not appear for Houston during those series.