Players · B · Pitcher · 2022

Ronald Bolaños

Kansas City Royals American League Central

Age: 26
B/T: R/R
Height: 6' 2"
Weight: 230 lb

Born: August 23, 1996 in Santa Cruz del Norte, Cuba
MLB debut: September 3, 2019

dbWAR: -.3
IP: 18.1
ERA: 4.42
FIP: 5.68
K/9: 5.9
FIP−: 143

Ronald Bolaños was a relief pitcher for the Kansas City Royals. In 2022 he struck out 12 batters over 18.1 innings across 8 appearances, going 0-0. His ERA of 4.42 was 11.3% higher than the league average of 3.97. Stripping out defence, his 5.68 FIP suggests that his ERA had some help behind him. He missed bats on 23.7% of swings (9.6% of every pitch he threw), walked 13.8% of the batters he faced and struck out 13.8%. His -0.3 dbWAR is built from that FIP rather than runs allowed, so it credits him for what he controls and not for the defence behind him.

League context

Percentile among qualified pitchers, 2022.

FIP5.68

K/95.9

WHIP1.75

WAR-.3

WAR by season

Pitching

Standard and advanced, by season.


2022	KC	8	0	18.1	0	20	9	12	12	4.42	5.68	1.75	5.9	5.9	111	143	-0.3
2021	KC	3	0	6.1	0	4	1	10	2	1.42	0.96	0.95	14.2	2.8	33	22	0.3
2020	KC	2	2	3.2	2	8	5	2	3	12.27	12.46	3.00	4.9	7.4	276	280	-0.3
2019	SD	5	3	19.2	2	17	13	19	12	5.95	5.25	1.47	8.7	5.5	132	116	0.0

Batting

Standard and advanced, by season.

																					Trend
2019	SD	3	5	0	0	1	0	0	4	.000	.000	.000	.000	.000	0.0%	80.0%	.000	-1.4	-124	-0.1	—

Platoon splits

How left- and right-handed hitters fare against him.

Season

Opponent batting by the side the hitter bats from, 2022. Counted from play-by-play, so totals can differ from the box-score season line by a plate appearance or two.
Split	PA	AB	H	HR	BB	SO	AVG	OBP	SLG	wOBA	K%
vs LHB	32	27	8	1	4	2	.296	.375	.519	.373	6.3%
vs RHB	55	43	12	1	8	10	.279	.418	.395	.372	18.2%

Pitch sequencing

What Ronald Bolaños throws in each count, and what he follows each pitch with. Select any cell for the breakdown.

ShowBatter

SinkerSliderFour-seamCurveballChangeup

Select a count to see exactly what Ronald Bolaños throws in it.

Pitch arsenal

What he throws, how hard, how often it misses, and what hitters do with it.

Season


Sinker	38.9%	129	92.9	2,197	37.2%	17.9%	33	.333	.840
Slider	30.1%	100	84.1	2,422	43.0%	44.2%	19	.211	.754
Four-Seam Fastball	15.7%	52	93.5	2,200	30.8%	5.3%	10	—	—
Curveball	10.5%	35	77.0	2,537	48.6%	15.4%	6	—	—
Changeup	4.8%	16	87.1	1,486	12.5%	0.0%	2	—	—

Ronald Bolaños's arsenal by usage. Velocity is average release speed in mph, spin in rpm, and whiff rate is misses per swing — the cleanest single measure of whether a pitch beats hitters. BAA and OPS are what hitters did against each pitch, credited to the one that ended the plate appearance, and are left blank under 15 at-bats.

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Ronald Bolaños

How these are computed

wOBA uses linear weights measured from this season's own play-by-play rather than published constants, and wRC+ is park-adjusted against that same league. dbWAR is our own open implementation — not fWAR or bWAR — and the full derivation, including its simplifications, is on the methodology page.