Aroldis Chapman has helped the Yankees have the best bullpen in baseball

The Yankees have the best bullpen in baseball once again. Their collective fWAR of 4.7 is 1^st by a wide margin, and they strike out a whopping 33% of the batters they face. Anchoring this great bullpen is predictably Aroldis Chapman, amidst maybe the best season of his career.

Chapman currently boasts a 1.14 ERA and a 1.23 FIP, 7^th and 2^nd respectively (min 30IP). Believe it or not though, he’s actually been getting better as the season goes on. Especially as of late, not allowing a run in the month of June.

These improvements didn’t happen by accident though, Chapman has made an adjustment, or has been slowly making one over the course of the first half.

He started the season in March/April throwing his fourseam fastball only 57% of the time, followed by his slider 30% of the time, and his new toy, a sinker 12% of the time. Which is in keeping with the Yankees’ staff wide strategy to throw less fastballs and more off-speed pitches.

Slowly but surely, Aroldis Chapman began morphing into his old self. His fourseam % is up to almost 74%, while his sinker usage is down 6%, and his slider % is down below 20%. This change in pitch usage has resulted in more strikes being thrown, his BB% in June is down to 9.4%. This improved command has also contributed to less good swings, his hard contact% is down from 38% to 28%.

No one strategy will work for every pitcher, consider Aroldis Chapman an example of this. Just because someone like Masahiro Tanaka excels while throwing mostly sliders and changeups, does not mean that Chapman should adopt this strategy. His best pitch by far, is his fastball, and I’ve always been a proponent of throwing your best pitch as much as possible.

On the other side of the coin though, baseball is a game of adjustments. Chapman has made his adjustment by throwing more fastballs. If I noticed this, I guarantee every team in the majors noticed it too. They will adjust in kind, and it will once again be on Chapman to tweak his approach, but we’ll cross that bridge when we get to it. For now enjoy his dominance.