When discussing the likelihood of a guy like Rowdy Hardy and his low-80's fastball becoming even a decent MLB pitcher, I always come back to the same question. While some aged vets who have been in MLB for 10+ years figure out how to succeed with that kind of velocity, has there ever been a young pitcher who came to the big leagues and succeeded with that kind of stuff?
Well, he hasn't succeeded yet, but the Reds have a pitcher somewhat like Hardy in Danny Herrera. The Reds acquired him with Edinson Volquez in the Josh Hamilton trade. Like Hardy, he's a lefty. And, like Hardy, he's an ultra-slowballer. He throws an 83 mph two-seam fastball and an 80 mph cutter. He also throws a lot of sliders and his best out pitch is a screwball/changeup. He has succeeded in the minors by relying on movement and changing speeds, a lot like Rowdy Hardy.
There are some differences. Herrera has made it to the majors at 23, while Hardy is still in AA at 25. And Herrera managed to get a good deal of strikeouts, at least in the low minors. And Herrera doesn't have Hardy's excellent control.
But at least there is one young major league pitcher with velocity similar to Hardy's. Maybe this provides a tiny sliver of hope for him.