Ritchie (elbow) was activated from the 60-day injured list and tossed five no-hit frames with one walk and seven strikeouts July 12 for Single-A Augusta.
Ritchie (elbow) allowed one hit and struck out one over two scoreless innings in his first rehab start with Atlanta's Florida Complex League affiliate on Monday.
Single-A Augusta placed Ritchie (elbow) on its 60-day injured list March 26.
Ritchie is scheduled to undergo season-ending Tommy John surgery Wednesday to repair a moderate UCL tear in his right elbow, Geoff Pontes of Baseball America reports.
Single-A Augusta placed Ritchie (undisclosed) on its 7-day injured list Thursday.
Ritchie left his most recent start for Single-A Augusta with an apparent injury, Garrett Spain of Battery Power reports.