Juan Nicasio Has a New Slider, and He Needs His Old One Back

The Mariners recently inked Juan Nicasio to a 2-year/$17-million deal in their first significant addition to their pitching staff this offseason. After years as a middling starter, Nicasio emerged as a rock-solid relief option with the Rockies in 2014 before the Dodgers fully bought into his potential as a reliever the following year. The Pirates then acquired him and shifted him into the rotation a bit in 2016; however, he had more success in their bullpen and moved there full-time in 2017. He was again on the move last year, though — this time playing for two new teams — but he never started a game, posting a cumulative 2.61 ERA over 72.1 IP in 76 appearances.

He’s on the wrong side of 30, and breakout relievers tend to pop up and decline quickly, but it can be argued that Nicasio has done nothing but improve since moving into the bullpen.

Juan Nicasio as RP	IP	ERA	AVG	OBP	SLG	wOBA
2014	20.2	3.48	.227	.275	.400	.300
2015	56.1	3.83	.257	.359	.381	.320
2016	55.2	3.88	.249	.328	.387	.308
2017	72.1	2.61	.216	.277	.333	.265

As a reliever, Nicasio is largely a two-pitch pitcher, primarily throwing a four-seam fastball and a slider. He had occasionally mixed in a sinker and changeup in previous years, but 2017 saw Nicasio throw a four-seam fastball or slider 98.31% of the time. This pitch mix in combination with his K/9 dipping from slightly over 10 to just under 9 may raise a couple eyebrows, but Nicasio also improved his command considerably.

His 6.9% BB% in 2017 was his lowest since his debut season and marked a second straight year of improvement, and his 24.7% K% compares well to previous years. This would suggest that Nicasio is only getting more efficient with his outs, not striking guys out at a lesser rate. And sure enough, his 1.08 WHIP last year was by far the lowest it’s ever been.

A quick look at his splits from 2017 showed a distinct improvement against left-handed batters compared to previous years.

Juan Nicasio vs. LHH	IP	AVG	OBP	SLG	wOBA
2015	14.1	.359	.494	.516	.427
2016	21.0	.241	.351	.476	.350
2017	33.0	.205	.252	.292	.235

In his largest sample yet, Nicasio made huge strides.

Since improvements against opposite-handed batters tend to suggest an improvement in a pitcher’s changeup or breaking ball, and given that Nicasio essentially throws just two pitches, his slider seemed like a good starting point. I found that (per Brooks Baseball) it had an entirely different shape in 2017.

Juan Nicasio Sliders	Velocity	HMov	VMov
2015	86.92	1.94	1.86
2016	87.11	1.49	2.80
2017	88.92	0.47	4.04

While Nicasio’s slider was laterally less impressive in 2017, it made up for that with reduced drop.

Here is his slider in 2016 with a little frisbee action.

And here it is in 2017 a bit more tightly wound.

Nicasio’s slider was devastating to right-handers in 2015 and 2016 (cumulative .218 wOBA/.221 xwOBA), but it seemingly fell into the swing path of lefties, as they smashed it for a .369 wOBA/.272 xwOBA in the same period. In 2017, lefties floundered against it for the first time, posting just a .194 wOBA/.175 xwOBA. But his other slider disappeared.

Using this somewhat cutter-like breaking ball against RHB in 2017 yielded a .302 wOBA and .320 xwOBA. Considering the fastball didn’t play up (.298 wOBA/.334 xwOBA), that kind of performance is a slight concern, but righties’ triple slash against him was still an encouraging .225/.296/.367 (.287 wOBA).

On the surface, the Mariners seem to have gotten a quality reliever at about market rate for his talent, but I think there is still some upside here. Certainly, in this new slider, Nicasio has found a legitimate weapon against LHB, but the Mariners must hope his natural slider is not lost. In order to remain a high-quality, high-leverage setup man — the kind that posts sub-3 ERAs — he’s going to have to bring out both.