The Guardians added Gaddis from Triple-A Columbus to serve as their 27th man Thursday, Mandy Bell of MLB.com reports.
Because Wednesday's game with the Dodgers ended up spilling into Thursday due to rain, the Guardians will be allowed to use Gaddis as an extra man in their bullpen. The 25-year-old righty has put up a 5.17 ERA and 1.21 WHIP through 31.1 frames in the majors this season, and he will likely return to Columbus immediately after Thursday's contest.