His average fastball is 92.0 mph. For comparison here are some other pitchers average fastballs. CC Sabathia 92.2, Johnny Cueto 92.2, Yovani Gallardo 91.8, Felix Hernandez 91.8. He's also 22 and pitching in the majors. Not many guys are dominating the majors at age 22. Just because he's not dominating doesn't mean he's not a good prospect or that he won't get better. That's the part you don't seem to understand. Younger players generally tend to get better. Amazing, I know.