The Science Behind Mariano Rivera's Cutter

Mariano Rivera of the New York Yankees became the all-time saves leader yesterday. We already knew he was the best. Now he has the career numbers to back it up. What is amazing is that he has done it largely with one pitch - his cut fastball.

Here is a good video demonstration by the NY Times on how Rivera throws his cutter and why it is so effective. And this Sport Science piece further shows why it is so difficult to hit. The break is so late, the batter must commit to swing before he knows where it's going. That late break is a product of maximum rotation and just the right finger pressure on the ball. Every pitcher's hand and delivery is different. But through experimentation, Rivera was able to find a pitch that works quite well for him.

For more on just how hard a pitch like this is to see, here's another Sport Science video about a batter's vision and timing. This is why they say hitting a 90 mph fastball is the hardest thing to do in sports. Throw in Rivera's late movement and it's nearly impossible.

A Little Leaguer will probably not be able replicate Rivera's cutter. He just doesn't have enough distance to work with in order to get that much movement on a fastball. But understanding the importance of experimenting with fastball grips and the vital role that rotation plays on movement are both valuable lessons for young pitchers today.