To clarify: Aroldis Chapman isn’t just one of the most dominant relief pitchers in MLB right now. He’s among the most dominant in the history of the game. Chapman strikes out people at a rate we’ve never seen before. That’s not hyperbole. His 15.2 K/9 ratio is the highest in MLB history.
Even casual baseball fans can watch Chapman and understand what makes him special. Fangraphs.com lists the average velocity on Chapman’s fastball at 100.4 MPH. Any pitcher that can reach triple digit velocity, even if it’s just on rare occasions, has elite, rare arm talent.