Alvarez was recalled from Triple-A Round Rock on Friday.
With Jeremy Jeffress being placed on the restricted list, Alvarez will return to the Rangers and provide additional bullpen depth. Alvarez has pitched just 1.2 innings with Texas this season, during which he allowed two runs off five hits. However, his performance with Round Rock has been much better. After six games (eight innings), Alvarez has a 2.25 ERA and 10 strikeouts.