Harris was called up from Triple-A Las Vegas and is expected to handle the bulk role Saturday against the Astros, Matt Kawahara of the San Francisco Chronicle reports.
Harris will operate in a bulk role, following opener Austin Pruitt in what will be Harris' second appearance with the Athletics on Saturday. The left-hander was walloped for six earned runs on one hit and five walks while hitting a batter over one-third inning against the Mets on April 14. Since being sent down April 15, Harris has produced a 3.42 ERA and 1.18 WHIP with 25 punchouts over 26.1 in six starts with Las Vegas. In a corresponding move, Adrian Martinez was optioned to Triple-A to create a spot for Harris on the major-league roster.