Middleton (elbow) will throw one inning in a rehab appearance for Triple-A Reno on Thursday, Nick Piecoro of the Arizona Republic reports.
Middleton, who has been sidelined since May 16, threw a bullpen session earlier this week, per Piecoro and Jose M. Romero of the Arizona Republic, suggesting a rehab stint was in the offing. The right-hander strung together five straight scoreless appearances before suffering the injury.