Here is a video explaining the reason why Rivera was effective.
<iframe width="560" height="315" src="https://www.youtube.com/embed/dMVXjRGTtG0" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
So:
a) The guy had *TWO* pitches--a drop and a cutter.
b) He had incredible control. He never threw a pitch over the middle of the plate.
c) His two pitches looked the same to the batter.
<iframe width="560" height="315" src="https://www.youtube.com/embed/dMVXjRGTtG0" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>
So:
a) The guy had *TWO* pitches--a drop and a cutter.
b) He had incredible control. He never threw a pitch over the middle of the plate.
c) His two pitches looked the same to the batter.
