Bass had his contract purchased from Triple-A Iowa on Monday, Mark Gonzales of the Chicago Tribune reports.
Bass will join the big club for the first time all season after compiling an impressive 2.28 ERA across 23.2 innings with Triple-A Iowa. He'll offer a fresh arm out of the bullpen after two of the team's relievers (Luke Farrell and Cory Mazzoni) tossed more than an inning of relief in Sunday's loss to the Pirates. Mazzoni was sent to the minors in a corresponding roster move.