Numbers Prove Aroldis Chapman's Slider is Far Less Effective Than Last Year

New York Yankees closer Aroldis Chapman may be losing his edge just a bit. Now, let's get this out of the way: statistically, Chapman is still having a very good season. His ERA is still at just 2.45 after a rough outing against the Rays Monday, and he's tied for the American League lead with 25 saves.

Still, though, when you dig deeper into the numbers, it's easy to see that Chapman's simply not the same pitcher he's been in the past:

While there was bound to be some natural regression from his insane strikeout percentage with the slider last season, it's very discouraging just how low that number has dropped, especially considering how frequently Chapman is using the pitch. However, it may not be the movement of the pitch or his command of it that's dropped off.

In fact, the ineffectiveness of Chapman's slider may actually have a lot to do with his fastball. In 2018, Aroldis threw his sizzling four-seam fastball 66% of the time, and opposing hitters batted a paltry .185 against the pitch. This season, though, the 30-year-old's average fastball velocity has dropped by nearly one full mile per hour, and hitters are raking against it at a clip of .288.

As a result, Chapman is using his fastball less (just 56% of the time), and he's unable to utilize it to effectively set up his slider.

While Chapman is still a top-tier reliever, these numbers indicate a concerning trend. It remains to be seen whether Chapman will be able to adapt his game with the inevitable decline of the velocity on which he's leaned so heavily throughout his career.