Chapman, 26, hasn't been on the mound since suffering a mild concussion and having a plate and screws inserted around his eye to repair bone following the incident on March 19. He played catch on Thursday and Friday at Great American Ball Park.
In a pregame chat with reporters Friday, Chapman was upbeat and said he's excited about returning to the mound.
The Reds haven't put a timetable on Chapman's return to the active roster.
Cincinnati (3-8) has been using a closer-by-committee approach in Chapman's absence, with left-hander Manny Parra accounting for the club's lone save. Right-hander J.J. Hoover squandered another opportunity.