Drabek, optioned to Las Vegas on June 14, gave up three runs while striking out eight to earn the victory on Tuesday against Salt Lake.
"[Drabek] had a good outing last night; [he] didn't use his fastball a lot for strikes," manager John Farrell said. "Fastball, curveball, changeup -- the changeup was above average. He pitched to contact and had very good stuff."
Drabek has had three starts since being demoted, and Farrell remains unsure when the righty will be called back up.
"With any player sent back to make adjustments, ultimately their consistency and their consistent performance will force the hand or generate the internal conversation that leads to that decision," Farrell said. "When he was sent out, there wasn't a date on the calendar."