Chicago Cubs reliever Brian Duensing had a stellar year out of the bullpen in 2017 and an abysmal 2018. What changed? His money pitch in 2017 was his slider. The 2018 version of the slider did not get the same results.
The first thing I want to look at is pitch execution of the slider. Notice below in 2017 he was very consistent at attacking down and in to righties/down and away to lefties.
Now let’s take a look at the 2018 slider.
His primary location in 2018 was still the same as 2017, but at a 9% decrease. The biggest difference I noticed is more sliders to the arm side. Typically pitchers are not trying to the throw the slider arm side unless the are trying to utilize it as a freeze pitch. The execution in 2017 is clearly better, which makes sense considering Duensing’s BB/9 rate sky rocketed from 2.6 to 6.9.
What happens when you start walking more people? Quality pitches that normally would get a chase are going to be taken more often. The ability to pound the zone is going to lead to more swing and misses out of the zone.
Now let’s examine Duensing’s release points in 2017 and 2018.
There is a clear progression in release point across the board from 2017 to 2018. With Duensing being on the DL two separate times due to shoulder problems, my thought is maybe this caused him to change his release point to compensate.
As a pitcher, it doesn’t take much to throw everything off. The reason for a change in release point could vary from an injury to a timing issue. If tempo in the delivery changes or the hand break is later or earlier, there is going to be a subtle change in release point. The use of an edgertronic camera would be a great tool to compare 2017 to 2018.
Getting Duensing’s release point back down to what it was in 2017 could lead to favorable results in 2019.