The Athletics recalled Alvarado from Triple-A Las Vegas on Friday, Jessica Kleinschmidt of Baseball America reports.
Alvarado appears set to make his MLB debut in the coming days. Alvarado has thrown 15.2 innings out of the bullpen for Las Vegas this season, registering 12.6 K/9 and a 3.45 ERA. He was claimed off waivers from the Pirates back in January.