For Yankees closer Aroldis Chapman, high-octane fastballs have been his game since he broke into the big leagues full-time in 2011. While Chapman's fastball still elicits mouth-opening radar gun marks on the scoreboard, he has realized that some added finesse to the top-notch velocity is a necessity.
Chapman averaged 98.6 mph with his four-seam fastball and 100.9 mph with his sinker in 2018, which ranked in the 100th percentile in the game, according to Baseball Savant. Add in a spin rate that positioned him in the 95th percentile among all pitchers, and Chapman's fastball remains one of the best weapons in the game. Yet the velocity is not enough.
In 2018, the left-handed Chapman increased the use of what was a very effective slider. Chapman utilized his signature velocity and the sweeping slider to help generate MLB's best K-rate in 2018 at 16.3 strikeouts per nine innings.
It's not all good news for Chapman. First, hitters have become better at catching up to high-speed offerings in general. Combine that with Chapman's decreasing velocity and a distinct flatness to a number of fastballs in 2018, and the results were a hard-hit rate of 32.1 percent, which was several percentage points higher than 2017.
Based on the increased usage of the slider in 2018 (25.4 percent of his pitches), it is clearly evident the Yankees -- with Chapman's full buy-in -- understand his slider has become as much a key as his fastball options. With a better slider, Chapman's fastball begins to liven up (despite decreased velocity) so long as he has full command of placement of all the offerings.
Unfortunately, command has always been an issue with Chapman. Considering it's the final key for advancing Chapman's modified repertoire there is no assurance that he'll be able to replicate his 2018 performance in 2019.
What remains to be seen is if Chapman will further sacrifice the number of fastballs thrown (either variety) for his slider in 2019. Regardless, the disparity of the number of pitches thrown between the three offerings is not nearly as important as how Chapman will play one pitch off the other. This will require he and his catcher, along with pitching coach Larry Rothschild, understanding within a given game what's working best.
That said, determining Chapman's comfort level with his pitches is a roller coaster ride. There were numerous appearances in 2018 in which Chapman experienced little to no feel for a particular pitch. That uneasiness often forced Chapman to become totally reliant on one pitch, which of course allowed hitters to zone in on the pitch he managed to get over the plate.
Chapman and the Yankees are wise to continue determining the correct variability of pitch sequencing along with persisted work on the effectiveness of the pitches. In Chapman's case in particular, if he turns in a stellar 2019 season, he can opt out of his current contract and see what the free-agent market bares. However, with Chapman pitching at age-32 in 2020, and age being an undoubted issue for MLB clubs and closers looking for significant deals (see Craig Kimbrel), chances are Chapman might stay put.
For 2019, Chapman's efforts must revolve around finding the best approach among his pitches and maintaining command of the entire repertoire on a more consistent basis. So long as Chapman continues to develop a comfort level with each of his pitches, he should provide the Yankees with results that will maintain his place among the best closers in the game.