The Reds transferred Warren (oblique) from the 10-day injured list to the 60-day IL on Wednesday.
Cincinnati's decision to shift Warren to the 60-day IL comes as little surprise after manager David Bell told Charlie Goldsmith of The Cincinnati Enquirer that Warren was at least a month away from rejoining the bullpen after only recently beginning to throw lightly off flat ground. The transaction ensures that Warren won't be an option for Cincinnati until around mid-September.