Medlen will start Friday against the Astros, Jack Magruder of FanRagSports.com reports.
With Robbie Ray expected to miss multiple starts with a Grade 2 oblique strain, the Diamondbacks will give Medlen the first opportunity to fill in for him in the rotation. The 32-year-old Medlen hasn't appeared in the majors since 2016 and owns an unremarkable 6.00 ERA and 1.50 WHIP through four starts with Triple-A Reno this season, but his prior big-league experience likely influenced the Diamondbacks' decision. Arizona will have to clear a spot for Medlen on its 40-man roster prior to Friday's game, which can easily be done by transferring Taijuan Walker (elbow) to the 60-day DL. With Medlen lining up against the defending World Series Champions, Friday may be a good opportunity to stack bats against the veteran right-hander.