He was getting minor leaguers out to the tune of a .355/.429/.613/1.041 OPS against in Louisville. That must be the new definition of effective right there.
Guardado's going to be 37 in less than two months, and his arm is shot. He's had a nice career, but his time is in the past. Unfortunately for the Reds, neither the front office nor Guardado have figured that out.