For years, kids have been taught at a young age to keep the ball low. Over the course of the past few years, we have learned that high fastballs have a higher effective velocity and therefore, when located correctly, can be very effective. On the other hand, breaking balls left up in the zone continue to end up in the stands. I was looking at pitchers who throw sliders up in the zone this year compared to those who threw sliders up in the zone from 2014-2015 and found something interesting. Take a look at the lowest opponent batting averages from 2014-2015:
Now look at the HIGHEST batting averages from this season:
We notice one name on both lists. Miguel Gonzalez. Gonazalez was traded from the White Sox to the Rangers on August 31st. He has never had great success in his career but has been serviceable with a career ERA below 4.00. Back to his incredible change in success with his slider. We could ask, is this just luck that played a role in his 2014-2015 slider or did his slider just get worse? We will start with if he got lucky. This season, the average BABIP among those who threw high sliders in the strike zone is .289. Miguel Gonzalez’s BABIP is an unreal .391. To give you an indication on just how unlucky he has gotten this season with high sliders, take a look at this plot:
Miguel Gonzalez is highlighted in red. He is clearly the most unlucky pitcher in this plot. So he is incredibly unlucky this season, but what about 2014-2015? The average BABIP for high sliders in the zone for those year was .295. Miguel Gonzalez checked in at a cool .150 those years which was the lowest. It is crazy to think that his luck has changed so much over the course of just 3 years. What makes it even crazier is the fact that hitters are making weaker contact by over 1 mph. So the answer to the first part of that question is yes, he has been on complete opposite sides of the spectrum when it comes to getting lucky on high sliders.
When we look at how the pitch itself is, there is something different in his delivery, specifically in his release. Here is his release chart from 2014-2015 compared to that of this season:
He seems to have a more inconsistent delivery this season. I am not sure if this is a planned adjustment or if this is just something that naturally occurred. In general, usually inconsistent deliveries are never a positive attribute. He previously had slightly more horizontal break on his slider in the past, but nothing substantial.
In general from what I was looking at players who threw sliders up in the zone (whether or not it was on purpose) and had success generally were top tier pitchers, while the ones who did not were bad pitchers. Miguel Gonzales did not seem to fit in with Ken Giles, Sonny Gray, and Andrew Miller in that first list. Sentenzala and Corbin have been bad, but Verlander and Porcello have both had their share of bad luck this season as well. Miguel doesn’t deserve to be in the really bad category either. He just happened to be on complete opposite ends of the spectrum when it comes to luck on sliders up in the zone.