Tapia, just promoted from Triple-A Las Vegas on Sunday, fired a perfect ninth inning in a loss to the Astros on Monday.
The journeyman reliever had to work a bit for his outs -- he fired 20 pitches overall during his one frame and induced eight foul balls -- but he got through his debut frame for Oakland unscathed. Tapia has enjoyed success in each of his prior big-league stints with the team and had posted a solid 3.24 ERA at Triple-A Las Vegas despite the hitter-friendly environment of the Pacific Coast League, so he could develop into a solid mid-to-later-inning option with a fair share of hold opportunities over time.