McCullers (back) will head out on a rehab appearance with Triple-A Fresno on Friday, Jake Kaplan of the Houston Chronicle reports.
McCullers was able to complete a 45-pitch simulated game Sunday, and has been deemed ready to face live hitting for the first time since going down with a back injury near the end of July. It hasn't been determined how many rehab appearances McCullers will need, but it's likely that the right-hander spends two games ramping up his endurance with Fresno before returning to the big-league team.